From 9f582b99d2a9671b95ce212ea0d4a894dae6b8f7 Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 02:47:42 +0100
Subject: [PATCH 01/14] chore: bun workspace scaffold

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .gitignore                            |   2 +
 CLAUDE.md                             | 123 +++++
 LICENSE                               | 661 ++++++++++++++++++++++++++
 README.md                             |  14 +
 apps/server/package.json              |   7 +
 apps/web/package.json                 |   7 +
 bun.lock                              |  95 ++++
 package.json                          |  16 +
 packages/contracts/package.json       |   7 +
 packages/contracts/test/smoke.test.ts |   2 +
 packages/core/package.json            |   7 +
 packages/course-format/package.json   |   7 +
 packages/db/package.json              |   7 +
 packages/feature-ai/package.json      |   7 +
 packages/feature-import/package.json  |   7 +
 packages/feature-learner/package.json |   7 +
 packages/feature-studio/package.json  |   7 +
 packages/ui/package.json              |   7 +
 tsconfig.json                         |  16 +
 19 files changed, 1006 insertions(+)
 create mode 100644 CLAUDE.md
 create mode 100644 LICENSE
 create mode 100644 README.md
 create mode 100644 apps/server/package.json
 create mode 100644 apps/web/package.json
 create mode 100644 bun.lock
 create mode 100644 package.json
 create mode 100644 packages/contracts/package.json
 create mode 100644 packages/contracts/test/smoke.test.ts
 create mode 100644 packages/core/package.json
 create mode 100644 packages/course-format/package.json
 create mode 100644 packages/db/package.json
 create mode 100644 packages/feature-ai/package.json
 create mode 100644 packages/feature-import/package.json
 create mode 100644 packages/feature-learner/package.json
 create mode 100644 packages/feature-studio/package.json
 create mode 100644 packages/ui/package.json
 create mode 100644 tsconfig.json

diff --git a/.gitignore b/.gitignore
index 95299e2..bc52024 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,5 @@ node_modules/
 *.log
 .env
 .worktrees/
+data/
+.cache/
diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 0000000..075473f
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,123 @@
+
+Default to using Bun instead of Node.js.
+
+- Use `bun <file>` instead of `node <file>` or `ts-node <file>`
+- Use `bun test` instead of `jest` or `vitest`
+- Use `bun build <file.html|file.ts|file.css>` instead of `webpack` or `esbuild`
+- Use `bun install` instead of `npm install` or `yarn install` or `pnpm install`
+- Use `bun run <script>` instead of `npm run <script>` or `yarn run <script>` or `pnpm run <script>`
+- Use `bunx <package> <command>` instead of `npx <package> <command>`
+- Bun automatically loads .env, so don't use dotenv.
+
+## APIs
+
+- `Bun.serve()` supports WebSockets, HTTPS, and routes. Don't use `express`.
+- `bun:sqlite` for SQLite. Don't use `better-sqlite3`.
+- `Bun.redis` for Redis. Don't use `ioredis`.
+- `Bun.sql` for Postgres. Don't use `pg` or `postgres.js`.
+- `WebSocket` is built-in. Don't use `ws`.
+- Prefer `Bun.file` over `node:fs`'s readFile/writeFile
+- Bun.$`ls` instead of execa.
+
+## Testing
+
+Use `bun test` to run tests.
+
+```ts#index.test.ts
+import { test, expect } from "bun:test";
+
+test("hello world", () => {
+  expect(1).toBe(1);
+});
+```
+
+## Frontend
+
+Use HTML imports with `Bun.serve()`. Don't use `vite`. HTML imports fully support React, CSS, Tailwind.
+
+Server:
+
+```ts#index.ts
+import index from "./index.html"
+
+Bun.serve({
+  routes: {
+    "/": index,
+    "/api/users/:id": {
+      GET: (req) => {
+        return new Response(JSON.stringify({ id: req.params.id }));
+      },
+    },
+  },
+  // optional websocket support
+  websocket: {
+    open: (ws) => {
+      ws.send("Hello, world!");
+    },
+    message: (ws, message) => {
+      ws.send(message);
+    },
+    close: (ws) => {
+      // handle close
+    }
+  },
+  development: {
+    hmr: true,
+    console: true,
+  }
+})
+```
+
+HTML files can import .tsx, .jsx or .js files directly and Bun's bundler will transpile & bundle automatically. `<link>` tags can point to stylesheets and Bun's CSS bundler will bundle.
+
+```html#index.html
+<html>
+  <body>
+    <h1>Hello, world!</h1>
+    <script type="module" src="./frontend.tsx"></script>
+  </body>
+</html>
+```
+
+With the following `frontend.tsx`:
+
+```tsx#frontend.tsx
+import React from "react";
+import { createRoot } from "react-dom/client";
+
+// import .css files directly and it works
+import './index.css';
+
+const root = createRoot(document.body);
+
+export default function Frontend() {
+  return <h1>Hello, world!</h1>;
+}
+
+root.render(<Frontend />);
+```
+
+Then, run index.ts
+
+```sh
+bun --hot ./index.ts
+```
+
+For more information, read the Bun API docs in `node_modules/bun-types/docs/**.mdx`.
+
+## Project rules
+
+Full design: `docs/superpowers/specs/2026-10-30-stcourses-design.md`. Plan: `docs/superpowers/plans/2026-10-30-stcourses.md`.
+
+- Bun only: `Bun.serve` routes and WebSockets, `bun:sqlite` or `Bun.sql`, `Bun.file`, `Bun.$`, `bun test`, `bun install`, `bunx`. Never express, vite, dotenv, pg, postgres.js, better-sqlite3, jest or vitest.
+- Frontend: a React SPA served via HTML imports. No Next.js. Plain CSS with custom properties; no Tailwind.
+- Course content is never stored in the database. Deleting the DB loses user data only.
+- Database URL is `STC_DATABASE_URL`: `sqlite://<path>` (default `sqlite://./data/stcourses.db`) or `postgres://...`. Every migration and query must run on both.
+- Idle memory: at most 2 GB for the deployment.
+- License: AGPL-3.0-only. Every package's `package.json` has `"license": "AGPL-3.0-only"`.
+- Never write into `/home/user/functional-programming-course` or `/home/user/systemic-design-course`; their manifests are overlays in `overlays/`.
+- Never commit anything from `/home/user/example_course_content` (licensed material, local test runs only).
+- Design tokens (spec 4.1): ground `#12141a`, side `#181b22`, raised `#232733`, line `#262a33`, line2 `#343947`; text `#d9dce3`, reading text `#d9d4c8`, heading `#f2efe8`, muted `#a4abb8`, faint `#8c93a0`; accent `#f1b44c`, accent-dim `#8c7440`. Fonts: IBM Plex Sans (UI), Literata (lesson titles and reading text, 19px / 1.75 in a 660px column), IBM Plex Mono (code). Dark theme only in v1.
+- Keyboard: arrow keys in the slide viewer, Escape closes overlays, normal Tab focus. No other shortcuts.
+- Commits: use the machine's git identity; every message ends with `Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>`.
+- Paths with spaces and non-ASCII characters must load, serve and download correctly. A broken overlay or manifest yields diagnostics, never a crash. Media serving supports Range (206/416) and returns 404 for paths escaping the course root.
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..be3f7b2
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,661 @@
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+
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+  9. Acceptance Not Required for Having Copies.
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+  You are not required to accept this License in order to receive or
+run a copy of the Program.  Ancillary propagation of a covered work
+occurring solely as a consequence of using peer-to-peer transmission
+to receive a copy likewise does not require acceptance.  However,
+nothing other than this License grants you permission to propagate or
+modify any covered work.  These actions infringe copyright if you do
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+covered work, you indicate your acceptance of this License to do so.
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+  10. Automatic Licensing of Downstream Recipients.
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+any patent claim is infringed by making, using, selling, offering for
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+
+  A patent license is "discriminatory" if it does not include within
+the scope of its coverage, prohibits the exercise of, or is
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+or that patent license was granted, prior to 28 March 2007.
+
+  Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+  12. No Surrender of Others' Freedom.
+
+  If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all.  For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+  13. Remote Network Interaction; Use with the GNU General Public License.
+
+  Notwithstanding any other provision of this License, if you modify the
+Program, your modified version must prominently offer all users
+interacting with it remotely through a computer network (if your version
+supports such interaction) an opportunity to receive the Corresponding
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+of the GNU General Public License that is incorporated pursuant to the
+following paragraph.
+
+  Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU General Public License into a single
+combined work, and to convey the resulting work.  The terms of this
+License will continue to apply to the part which is the covered work,
+but the work with which it is combined will remain governed by version
+3 of the GNU General Public License.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU Affero General Public License from time to time.  Such new versions
+will be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU Affero General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU Affero General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU Affero General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
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+author or copyright holder as a result of your choosing to follow a
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+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
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+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
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+  16. Limitation of Liability.
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+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
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+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If your software can interact with users remotely through a computer
+network, you should also make sure that it provides a way for users to
+get its source.  For example, if your program is a web application, its
+interface could display a "Source" link that leads users to an archive
+of the code.  There are many ways you could offer source, and different
+solutions will be better for different programs; see section 13 for the
+specific requirements.
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU AGPL, see
+<https://www.gnu.org/licenses/>.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..8a91f53
--- /dev/null
+++ b/README.md
@@ -0,0 +1,14 @@
+# STCourses
+
+STCourses is a self-hosted course platform. Homelabbers, universities and companies host their own courses, plus material they already own such as Packt video packages or Pluralsight slide PDFs, in one place that tracks progress. Authors write in Markdown in a git repo or in a browser studio; both edit the same files. Each install has one owner and is not multi-tenant.
+
+## Development
+
+```
+bun install          # install workspace dependencies
+bun test             # run all tests
+bun run typecheck    # tsc --noEmit
+bun run dev          # start the server with hot reload
+```
+
+License: AGPL-3.0-only.
diff --git a/apps/server/package.json b/apps/server/package.json
new file mode 100644
index 0000000..7c86da9
--- /dev/null
+++ b/apps/server/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "@stc/server",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "license": "AGPL-3.0-only"
+}
diff --git a/apps/web/package.json b/apps/web/package.json
new file mode 100644
index 0000000..797fba0
--- /dev/null
+++ b/apps/web/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "@stc/web",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "license": "AGPL-3.0-only"
+}
diff --git a/bun.lock b/bun.lock
new file mode 100644
index 0000000..d461254
--- /dev/null
+++ b/bun.lock
@@ -0,0 +1,95 @@
+{
+  "lockfileVersion": 1,
+  "configVersion": 1,
+  "workspaces": {
+    "": {
+      "name": "stcourses",
+      "devDependencies": {
+        "@types/react": "^19",
+        "bun-types": "^1.3.14",
+        "typescript": "^5",
+      },
+    },
+    "apps/server": {
+      "name": "@stc/server",
+      "version": "0.0.0",
+    },
+    "apps/web": {
+      "name": "@stc/web",
+      "version": "0.0.0",
+    },
+    "packages/contracts": {
+      "name": "@stc/contracts",
+      "version": "0.0.0",
+    },
+    "packages/core": {
+      "name": "@stc/core",
+      "version": "0.0.0",
+    },
+    "packages/course-format": {
+      "name": "@stc/course-format",
+      "version": "0.0.0",
+    },
+    "packages/db": {
+      "name": "@stc/db",
+      "version": "0.0.0",
+    },
+    "packages/feature-ai": {
+      "name": "@stc/feature-ai",
+      "version": "0.0.0",
+    },
+    "packages/feature-import": {
+      "name": "@stc/feature-import",
+      "version": "0.0.0",
+    },
+    "packages/feature-learner": {
+      "name": "@stc/feature-learner",
+      "version": "0.0.0",
+    },
+    "packages/feature-studio": {
+      "name": "@stc/feature-studio",
+      "version": "0.0.0",
+    },
+    "packages/ui": {
+      "name": "@stc/ui",
+      "version": "0.0.0",
+    },
+  },
+  "packages": {
+    "@stc/contracts": ["@stc/contracts@workspace:packages/contracts"],
+
+    "@stc/core": ["@stc/core@workspace:packages/core"],
+
+    "@stc/course-format": ["@stc/course-format@workspace:packages/course-format"],
+
+    "@stc/db": ["@stc/db@workspace:packages/db"],
+
+    "@stc/feature-ai": ["@stc/feature-ai@workspace:packages/feature-ai"],
+
+    "@stc/feature-import": ["@stc/feature-import@workspace:packages/feature-import"],
+
+    "@stc/feature-learner": ["@stc/feature-learner@workspace:packages/feature-learner"],
+
+    "@stc/feature-studio": ["@stc/feature-studio@workspace:packages/feature-studio"],
+
+    "@stc/server": ["@stc/server@workspace:apps/server"],
+
+    "@stc/ui": ["@stc/ui@workspace:packages/ui"],
+
+    "@stc/web": ["@stc/web@workspace:apps/web"],
+
+    "@types/node": ["@types/node@26.6.6", "", { "dependencies": { "undici-types": "~8.9.0" } }, "sha512-MzQj+8Kx3XI40OmUAE6Qoh58ZMNstNNMwn2nfd3qWsfe7nDNSqJNzes4njhz6AHwrSHOffSLwXU6yb474Q4aog=="],
+
+    "@types/react": ["@types/react@19.3.0", "", { "dependencies": { "csstype": "^3.2.2" } }, "sha512-N0rFCuH9YoxG9/m61l9MfpJKfmLOVU0em7ipIz6TRgSSkvReLB9vL85GB+yr8Bs5leqpvg96JSwF4ZS1s4viQg=="],
+
+    "bun-types": ["bun-types@1.4.4", "", { "dependencies": { "@types/node": "*", "undici-types": "*" } }, "sha512-yjrJh5oGX7mMPKGd19YXyIjmEuj4G4zNC30bs7PM9Az7NQ3ndF3j6hbeRdvJTRQEhJ/FYQwW0a2moweEi2hMxQ=="],
+
+    "csstype": ["csstype@3.2.3", "", {}, "sha512-z1HGKcYy2xA8AGQfwrn0PAy+PB7X/GSj3UVJW9qKyn43xWa+gl5nXmU4qqLMRzWVLFC8KusUX8T/0kCiOYpAIQ=="],
+
+    "typescript": ["typescript@5.9.3", "", { "bin": { "tsc": "bin/tsc", "tsserver": "bin/tsserver" } }, "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw=="],
+
+    "undici-types": ["undici-types@8.12.3", "", {}, "sha512-EXE4ydL3S76dFb27UFjNVZHTyv/TLdATj/KUe29ptdcg6qXL48J2tZ3126E5kICj5jn781OR+XlVH1N6Mz8jbA=="],
+
+    "@types/node/undici-types": ["undici-types@8.9.0", "", {}, "sha512-KTDyRTYX8sWmKXAikPHHSyc63CRPETMctyjKFupcC6OBLXT3xsN0e9aF7m+mIXutFWpUXuedtowG7iLOzp0kQg=="],
+  }
+}
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..341e6f2
--- /dev/null
+++ b/package.json
@@ -0,0 +1,16 @@
+{
+  "name": "stcourses",
+  "private": true,
+  "license": "AGPL-3.0-only",
+  "workspaces": ["packages/*", "apps/*"],
+  "scripts": {
+    "test": "bun test",
+    "typecheck": "bunx tsc --noEmit -p .",
+    "dev": "bun --hot apps/server/src/main.ts"
+  },
+  "devDependencies": {
+    "@types/react": "^19",
+    "bun-types": "^1.3.14",
+    "typescript": "^5"
+  }
+}
diff --git a/packages/contracts/package.json b/packages/contracts/package.json
new file mode 100644
index 0000000..0f09342
--- /dev/null
+++ b/packages/contracts/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "@stc/contracts",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "license": "AGPL-3.0-only"
+}
diff --git a/packages/contracts/test/smoke.test.ts b/packages/contracts/test/smoke.test.ts
new file mode 100644
index 0000000..8def1af
--- /dev/null
+++ b/packages/contracts/test/smoke.test.ts
@@ -0,0 +1,2 @@
+import { expect, test } from "bun:test";
+test("smoke", () => { expect(1).toBe(1); });
diff --git a/packages/core/package.json b/packages/core/package.json
new file mode 100644
index 0000000..dcd395b
--- /dev/null
+++ b/packages/core/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "@stc/core",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "license": "AGPL-3.0-only"
+}
diff --git a/packages/course-format/package.json b/packages/course-format/package.json
new file mode 100644
index 0000000..bbe81b8
--- /dev/null
+++ b/packages/course-format/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "@stc/course-format",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "license": "AGPL-3.0-only"
+}
diff --git a/packages/db/package.json b/packages/db/package.json
new file mode 100644
index 0000000..60f3f7b
--- /dev/null
+++ b/packages/db/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "@stc/db",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "license": "AGPL-3.0-only"
+}
diff --git a/packages/feature-ai/package.json b/packages/feature-ai/package.json
new file mode 100644
index 0000000..689f090
--- /dev/null
+++ b/packages/feature-ai/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "@stc/feature-ai",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "license": "AGPL-3.0-only"
+}
diff --git a/packages/feature-import/package.json b/packages/feature-import/package.json
new file mode 100644
index 0000000..cab5a10
--- /dev/null
+++ b/packages/feature-import/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "@stc/feature-import",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "license": "AGPL-3.0-only"
+}
diff --git a/packages/feature-learner/package.json b/packages/feature-learner/package.json
new file mode 100644
index 0000000..ae4cba9
--- /dev/null
+++ b/packages/feature-learner/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "@stc/feature-learner",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "license": "AGPL-3.0-only"
+}
diff --git a/packages/feature-studio/package.json b/packages/feature-studio/package.json
new file mode 100644
index 0000000..0e7914e
--- /dev/null
+++ b/packages/feature-studio/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "@stc/feature-studio",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "license": "AGPL-3.0-only"
+}
diff --git a/packages/ui/package.json b/packages/ui/package.json
new file mode 100644
index 0000000..ddb275b
--- /dev/null
+++ b/packages/ui/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "@stc/ui",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "license": "AGPL-3.0-only"
+}
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..c65f708
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,16 @@
+{
+  "compilerOptions": {
+    "target": "ESNext",
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "strict": true,
+    "jsx": "react-jsx",
+    "types": ["bun-types"],
+    "skipLibCheck": true,
+    "noEmit": true,
+    "allowImportingTsExtensions": true,
+    "baseUrl": ".",
+    "paths": { "@stc/*": ["packages/*/src"] }
+  },
+  "include": ["packages/*/src", "packages/*/test", "apps/*/src"]
+}

From 3b15d87a5f0055584089b94791dc17598080f47d Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 02:48:10 +0100
Subject: [PATCH 02/14] feat(contracts): shared server, exercise, ai, import
 and web interfaces

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 packages/contracts/src/ai.ts          |  3 ++
 packages/contracts/src/exercise.ts    |  7 ++++
 packages/contracts/src/import.ts      |  2 +
 packages/contracts/src/index.ts       |  5 +++
 packages/contracts/src/server.ts      | 28 ++++++++++++++
 packages/contracts/src/web.ts         |  4 ++
 packages/contracts/test/types.test.ts | 54 +++++++++++++++++++++++++++
 7 files changed, 103 insertions(+)
 create mode 100644 packages/contracts/src/ai.ts
 create mode 100644 packages/contracts/src/exercise.ts
 create mode 100644 packages/contracts/src/import.ts
 create mode 100644 packages/contracts/src/index.ts
 create mode 100644 packages/contracts/src/server.ts
 create mode 100644 packages/contracts/src/web.ts
 create mode 100644 packages/contracts/test/types.test.ts

diff --git a/packages/contracts/src/ai.ts b/packages/contracts/src/ai.ts
new file mode 100644
index 0000000..e0815c1
--- /dev/null
+++ b/packages/contracts/src/ai.ts
@@ -0,0 +1,3 @@
+export interface ChatMessage { role: "system" | "user" | "assistant" | "tool"; content: string; toolCallId?: string; name?: string }
+export interface ToolSpec { name: string; description: string; inputSchema: Record<string, unknown> }
+export interface AiProvider { id: string; chat(messages: ChatMessage[], opts: { tools?: ToolSpec[]; signal?: AbortSignal }): AsyncIterable<{ text?: string; toolCall?: { id: string; name: string; input: unknown } }> }
diff --git a/packages/contracts/src/exercise.ts b/packages/contracts/src/exercise.ts
new file mode 100644
index 0000000..54723c5
--- /dev/null
+++ b/packages/contracts/src/exercise.ts
@@ -0,0 +1,7 @@
+// Browser-runnable exercises (spec 4.3 type 6)
+export type ExerciseLanguage = "js" | "ts";
+export interface Assert { equal(actual: unknown, expected: unknown, message?: string): void; deepEqual(actual: unknown, expected: unknown, message?: string): void; ok(value: unknown, message?: string): void }
+export interface ExerciseTest { name: string; run(mod: Record<string, unknown>, assert: Assert): void | Promise<void> }
+// A tests file is an ES module: `export const tests: ExerciseTest[]`. Learner code is an ES module.
+export interface TestResult { name: string; passed: boolean; message?: string; expected?: string; actual?: string }
+export interface ExerciseRunner { language: ExerciseLanguage; run(learnerCode: string, testsModule: string, timeoutMs: number): Promise<TestResult[]> }
diff --git a/packages/contracts/src/import.ts b/packages/contracts/src/import.ts
new file mode 100644
index 0000000..dc75989
--- /dev/null
+++ b/packages/contracts/src/import.ts
@@ -0,0 +1,2 @@
+export interface ImportSource { kind: "packt-video" | "pdf-deck" | "code-repo" | "video-folder"; path: string; options?: Record<string, unknown> }
+export interface ImportResult { courseId: string; manifestPath: string; warnings: string[] }
diff --git a/packages/contracts/src/index.ts b/packages/contracts/src/index.ts
new file mode 100644
index 0000000..859b47a
--- /dev/null
+++ b/packages/contracts/src/index.ts
@@ -0,0 +1,5 @@
+export * from "./server";
+export * from "./exercise";
+export * from "./ai";
+export * from "./import";
+export * from "./web";
diff --git a/packages/contracts/src/server.ts b/packages/contracts/src/server.ts
new file mode 100644
index 0000000..dbfca4a
--- /dev/null
+++ b/packages/contracts/src/server.ts
@@ -0,0 +1,28 @@
+export type Role = "owner" | "author" | "learner";
+export interface AuthUser { id: string; email: string; name: string; roles: Role[]; groups: string[] }
+export interface RequestContext { user: AuthUser | null; params: Record<string, string>; url: URL }
+export type RouteHandler = (req: Request, rc: RequestContext) => Response | Promise<Response>;
+export interface Feature {
+  name: string;                                   // "learner" | "import" | "studio" | "ai" | "core"
+  routes: Record<string, Partial<Record<"GET"|"POST"|"PUT"|"PATCH"|"DELETE", RouteHandler>>>; // paths start with /api/
+  jobs?: Record<string, JobHandler>;              // job kind -> handler
+}
+export interface JobContext { reportProgress(fraction: number, message?: string): Promise<void>; signal: AbortSignal }
+export type JobHandler = (payload: unknown, jc: JobContext) => Promise<unknown>;
+export type JobStatus = "queued" | "running" | "done" | "failed";
+export interface JobRecord { id: string; kind: string; status: JobStatus; progress: number; message: string | null; payload: unknown; result: unknown; error: string | null; createdAt: string; updatedAt: string }
+export interface JobQueue { enqueue(kind: string, payload: unknown): Promise<string>; get(id: string): Promise<JobRecord | null>; list(kind?: string): Promise<JobRecord[]> }
+export interface AuthService { userFromRequest(req: Request): Promise<AuthUser | null> }
+// Placeholders until Task 4 (@stc/db) and Task 7 (@stc/course-format) exist; switch to the real imports in Task 7.
+type Db = unknown;
+type CourseRepository = unknown;
+export interface ServerContext {
+  config: AppConfig; db: Db; courses: CourseRepository;
+  jobs: JobQueue; auth: AuthService;
+}
+export interface AppConfig {
+  port: number; databaseUrl: string; dataDir: string;       // dataDir holds cache/, media/, worktrees/
+  courseDirs: string[];                                      // folders scanned for stcourse.yaml (course repos and overlays/)
+  secret: string;                                            // STC_SECRET, used to encrypt BYOK keys
+  publicUrl: string;
+}
diff --git a/packages/contracts/src/web.ts b/packages/contracts/src/web.ts
new file mode 100644
index 0000000..2b7717c
--- /dev/null
+++ b/packages/contracts/src/web.ts
@@ -0,0 +1,4 @@
+import type React from "react";
+
+export interface WebRoute { path: string; element: () => Promise<{ default: React.ComponentType }>; nav?: { label: string; area: "header" | "admin" } }
+export interface WebFeature { name: string; routes: WebRoute[] }
diff --git a/packages/contracts/test/types.test.ts b/packages/contracts/test/types.test.ts
new file mode 100644
index 0000000..ebf1370
--- /dev/null
+++ b/packages/contracts/test/types.test.ts
@@ -0,0 +1,54 @@
+import { expect, test } from "bun:test";
+import type {
+  AiProvider, AppConfig, AuthService, AuthUser, Assert, ChatMessage, ExerciseRunner, ExerciseTest,
+  Feature, ImportResult, ImportSource, JobContext, JobHandler, JobQueue, JobRecord, RequestContext,
+  RouteHandler, ServerContext, TestResult, ToolSpec, WebFeature, WebRoute,
+} from "../src/index";
+
+test("contract interfaces accept well-formed literals", async () => {
+  const user: AuthUser = { id: "u1", email: "a@b.c", name: "A", roles: ["owner", "learner"], groups: ["g"] };
+  const rc: RequestContext = { user, params: { id: "1" }, url: new URL("http://localhost/api/x") };
+  const handler: RouteHandler = async () => new Response("ok");
+  const jobHandler: JobHandler = async (_p, jc) => { await jc.reportProgress(0.5, "half"); return null; };
+  const feature: Feature = {
+    name: "core",
+    routes: { "/api/health": { GET: handler, POST: handler } },
+    jobs: { noop: jobHandler },
+  };
+  const jc: JobContext = { reportProgress: async () => {}, signal: new AbortController().signal };
+  const record: JobRecord = {
+    id: "j1", kind: "noop", status: "queued", progress: 0, message: null, payload: {}, result: null,
+    error: null, createdAt: "2026-01-01T00:00:00Z", updatedAt: "2026-01-01T00:00:00Z",
+  };
+  const queue: JobQueue = { enqueue: async () => "j1", get: async () => record, list: async () => [record] };
+  const auth: AuthService = { userFromRequest: async () => user };
+  const config: AppConfig = {
+    port: 3000, databaseUrl: "sqlite://./data/stcourses.db", dataDir: "./data", courseDirs: ["./overlays"],
+    secret: "s", publicUrl: "http://localhost:3000",
+  };
+  const ctx: Pick<ServerContext, "config" | "jobs" | "auth"> = { config, jobs: queue, auth };
+
+  const assert: Assert = { equal() {}, deepEqual() {}, ok() {} };
+  const t: ExerciseTest = { name: "t", run: (_mod, a) => a.ok(true) };
+  const runner: ExerciseRunner = {
+    language: "ts",
+    run: async () => [{ name: "t", passed: true } satisfies TestResult],
+  };
+  const msg: ChatMessage = { role: "user", content: "hi" };
+  const tool: ToolSpec = { name: "x", description: "d", inputSchema: {} };
+  const provider: AiProvider = {
+    id: "p",
+    async *chat() { yield { text: "hi" }; yield { toolCall: { id: "1", name: "x", input: {} } }; },
+  };
+  const source: ImportSource = { kind: "pdf-deck", path: "/tmp/a.pdf", options: {} };
+  const result: ImportResult = { courseId: "c", manifestPath: "/tmp/stcourse.yaml", warnings: [] };
+  const route: WebRoute = {
+    path: "/", element: async () => ({ default: () => null }), nav: { label: "Home", area: "header" },
+  };
+  const web: WebFeature = { name: "learner", routes: [route] };
+
+  expect(typeof feature.routes).toBe("object");
+  expect(await queue.enqueue("noop", {})).toBe("j1");
+  expect((await runner.run("", "", 1000))[0]!.passed).toBe(true);
+  void [rc, jc, ctx, assert, t, msg, tool, provider, source, result, web];
+});

From 7e7ce3053513e6775fb235d1495657274cf35421 Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 02:49:42 +0100
Subject: [PATCH 03/14] feat(course-format): stcourse.yaml schema

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 bun.lock                                   |   5 +
 packages/course-format/package.json        |   5 +-
 packages/course-format/src/schema.ts       | 111 +++++++++++++++++++++
 packages/course-format/test/schema.test.ts |  51 ++++++++++
 4 files changed, 171 insertions(+), 1 deletion(-)
 create mode 100644 packages/course-format/src/schema.ts
 create mode 100644 packages/course-format/test/schema.test.ts

diff --git a/bun.lock b/bun.lock
index d461254..736e0ae 100644
--- a/bun.lock
+++ b/bun.lock
@@ -29,6 +29,9 @@
     "packages/course-format": {
       "name": "@stc/course-format",
       "version": "0.0.0",
+      "dependencies": {
+        "zod": "^4.6.7",
+      },
     },
     "packages/db": {
       "name": "@stc/db",
@@ -90,6 +93,8 @@
 
     "undici-types": ["undici-types@8.12.3", "", {}, "sha512-EXE4ydL3S76dFb27UFjNVZHTyv/TLdATj/KUe29ptdcg6qXL48J2tZ3126E5kICj5jn781OR+XlVH1N6Mz8jbA=="],
 
+    "zod": ["zod@4.6.7", "", {}, "sha512-g8W2D2kU6a8untc053fX1uVBKzM7yqAxW/3zwk83+6RyF2+SKOuV+c0wBDhUwzV1PaGapmZH+rmcUzPf+3CGwg=="],
+
     "@types/node/undici-types": ["undici-types@8.9.0", "", {}, "sha512-KTDyRTYX8sWmKXAikPHHSyc63CRPETMctyjKFupcC6OBLXT3xsN0e9aF7m+mIXutFWpUXuedtowG7iLOzp0kQg=="],
   }
 }
diff --git a/packages/course-format/package.json b/packages/course-format/package.json
index bbe81b8..935c4e7 100644
--- a/packages/course-format/package.json
+++ b/packages/course-format/package.json
@@ -3,5 +3,8 @@
   "version": "0.0.0",
   "private": true,
   "type": "module",
-  "license": "AGPL-3.0-only"
+  "license": "AGPL-3.0-only",
+  "dependencies": {
+    "zod": "^4.6.7"
+  }
 }
diff --git a/packages/course-format/src/schema.ts b/packages/course-format/src/schema.ts
new file mode 100644
index 0000000..b488cd7
--- /dev/null
+++ b/packages/course-format/src/schema.ts
@@ -0,0 +1,111 @@
+import { z } from "zod";
+
+const Track = z.object({ id: z.string(), label: z.string() });
+const Deck = z.object({
+  id: z.string(),
+  file: z.string(),
+  title: z.string().optional(),
+  attachTo: z.string(), // a lesson id or module id
+});
+const Attachment = z.object({ file: z.string(), title: z.string().optional(), module: z.string().optional() });
+
+const Lesson = z.object({
+  id: z.string(),
+  title: z.string(),
+  type: z.enum(["text", "video", "exercise"]),
+  file: z.string().optional(),
+  anchor: z.string().optional(),
+  duration: z.number().optional(), // seconds
+  transcript: z.string().optional(),
+  tracks: z.record(z.string(), z.object({ file: z.string().optional(), command: z.string().optional() })).optional(),
+  hints: z.object({ file: z.string(), match: z.string() }).optional(),
+  browser: z
+    .object({
+      language: z.enum(["js", "ts"]),
+      starter: z.string(),
+      tests: z.string(),
+      solution: z.string().optional(),
+    })
+    .optional(),
+  localCommand: z.union([z.string(), z.record(z.string(), z.string())]).optional(),
+});
+
+const Module = z.object({
+  id: z.string(),
+  title: z.string(),
+  code: z.object({ dir: z.string(), command: z.string().optional() }).optional(),
+  lessons: z.array(Lesson),
+});
+
+export const ManifestSchema = z
+  .object({
+    schema: z.literal(1),
+    id: z.string().regex(/^[a-z0-9][a-z0-9-]*$/),
+    title: z.string(),
+    pitch: z.string().optional(),
+    authors: z.array(z.string()).optional(),
+    root: z.string().optional(),
+    cover: z.string().optional(),
+    accent: z.string().regex(/^#[0-9a-fA-F]{6}$/).optional(),
+    collections: z.array(z.string()).optional(),
+    visibility: z.enum(["public", "signed-in", "restricted"]).default("restricted"),
+    gating: z.enum(["none", "sequential"]).default("none"),
+    tracks: z.array(Track).optional(),
+    mentor: z.string().optional(),
+    source: z
+      .object({
+        kind: z.enum(["authored", "packt-video", "pdf-deck", "code-repo", "video-folder"]),
+        origin: z.string().optional(),
+        importedAt: z.string().optional(),
+      })
+      .optional(),
+    decks: z.array(Deck).optional(),
+    attachments: z.array(Attachment).optional(),
+    modules: z.array(Module),
+  })
+  .superRefine((m, ctx) => {
+    const lessonIds = new Set<string>();
+    const moduleIds = new Set(m.modules.map((x) => x.id));
+    m.modules.forEach((mod, mi) => {
+      mod.lessons.forEach((l, li) => {
+        const path = ["modules", mi, "lessons", li];
+        if (lessonIds.has(l.id)) {
+          ctx.addIssue({ code: "custom", path: [...path, "id"], message: `duplicate lesson id "${l.id}"` });
+        }
+        lessonIds.add(l.id);
+        if ((l.type === "text" || l.type === "video") && !l.file) {
+          ctx.addIssue({ code: "custom", path: [...path, "file"], message: `file is required for ${l.type} lessons` });
+        }
+      });
+    });
+    m.decks?.forEach((d, i) => {
+      if (!lessonIds.has(d.attachTo) && !moduleIds.has(d.attachTo)) {
+        ctx.addIssue({
+          code: "custom",
+          path: ["decks", i, "attachTo"],
+          message: `attachTo "${d.attachTo}" is not a lesson or module id`,
+        });
+      }
+    });
+  });
+
+export type Manifest = z.infer<typeof ManifestSchema>;
+export type Module = z.infer<typeof Module>;
+export type Lesson = z.infer<typeof Lesson>;
+export type Deck = z.infer<typeof Deck>;
+export type Attachment = z.infer<typeof Attachment>;
+export type Track = z.infer<typeof Track>;
+
+export function parseManifest(
+  yamlText: string,
+): { ok: true; manifest: Manifest } | { ok: false; errors: string[] } {
+  let raw: unknown;
+  try {
+    raw = Bun.YAML.parse(yamlText);
+  } catch (e) {
+    return { ok: false, errors: [`yaml: ${e instanceof Error ? e.message : String(e)}`] };
+  }
+  const r = ManifestSchema.safeParse(raw);
+  if (r.success) return { ok: true, manifest: r.data };
+  return { ok: false, errors: r.error.issues.map((i) => `${i.path.join(".") || "(root)"}: ${i.message}`) };
+}
diff --git a/packages/course-format/test/schema.test.ts b/packages/course-format/test/schema.test.ts
new file mode 100644
index 0000000..16a64fa
--- /dev/null
+++ b/packages/course-format/test/schema.test.ts
@@ -0,0 +1,51 @@
+import { describe, expect, test } from "bun:test";
+import { parseManifest } from "../src/schema";
+
+const base = (extra = "", lessons = "      - { id: l1, title: One, type: text, file: a.md }") =>
+  `schema: 1\nid: x\ntitle: X\n${extra}modules:\n  - id: m1\n    title: M\n    lessons:\n${lessons}\n`;
+
+describe("parseManifest", () => {
+  test("parses a minimal manifest", () => {
+    const r = parseManifest(base());
+    expect(r.ok).toBe(true);
+    if (r.ok) {
+      expect(r.manifest.visibility).toBe("restricted");
+      expect(r.manifest.gating).toBe("none");
+    }
+  });
+
+  test("rejects a bad accent", () => {
+    const r = parseManifest(base('accent: "orange"\n'));
+    expect(r.ok).toBe(false);
+    if (!r.ok) expect(r.errors.some((e) => e.includes("accent"))).toBe(true);
+  });
+
+  test("rejects duplicate lesson ids across modules", () => {
+    const text = base() + "  - id: m2\n    title: M2\n    lessons:\n      - { id: l1, title: Dup, type: text, file: b.md }\n";
+    const r = parseManifest(text);
+    expect(r.ok).toBe(false);
+    if (!r.ok) expect(r.errors.some((e) => e.includes("l1"))).toBe(true);
+  });
+
+  test("requires file for text and video lessons", () => {
+    for (const type of ["text", "video"]) {
+      const r = parseManifest(base("", `      - { id: l1, title: One, type: ${type} }`));
+      expect(r.ok).toBe(false);
+      if (!r.ok) expect(r.errors.some((e) => e.includes("file"))).toBe(true);
+    }
+    expect(parseManifest(base("", "      - { id: l1, title: One, type: exercise }")).ok).toBe(true);
+  });
+
+  test("rejects a deck whose attachTo is not a lesson or module id", () => {
+    const r = parseManifest(base("decks:\n  - { id: d1, file: d.pdf, attachTo: nope }\n"));
+    expect(r.ok).toBe(false);
+    if (!r.ok) expect(r.errors.some((e) => e.includes("nope"))).toBe(true);
+    expect(parseManifest(base("decks:\n  - { id: d1, file: d.pdf, attachTo: m1 }\n")).ok).toBe(true);
+  });
+
+  test("rejects schema: 2", () => {
+    const r = parseManifest(base().replace("schema: 1", "schema: 2"));
+    expect(r.ok).toBe(false);
+    if (!r.ok) expect(r.errors.some((e) => e.startsWith("schema"))).toBe(true);
+  });
+});

From 7a68800f6faaea08caa1bbc16ab0ae7ff79d4ebf Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 02:50:00 +0100
Subject: [PATCH 04/14] test: sample fixture course

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 fixtures/courses/sample/MENTOR.md             |   1 +
 .../sample/code/S01 - First steps/hello.sh    |   1 +
 .../courses/sample/exercises/add/solution.js  |   3 ++
 .../courses/sample/exercises/add/starter.js   |   3 ++
 .../courses/sample/exercises/add/tests.js     |   4 ++
 fixtures/courses/sample/lessons/01-intro.md   |   3 ++
 fixtures/courses/sample/lessons/02-video.md   |   3 ++
 fixtures/courses/sample/lessons/03-code.md    |   7 ++++
 .../courses/sample/lessons/04-exercise.md     |  23 ++++++++++++
 fixtures/courses/sample/media/clip.mp4        | Bin 0 -> 3934 bytes
 fixtures/courses/sample/media/deck.pdf        | Bin 0 -> 1454 bytes
 fixtures/courses/sample/stcourse.yaml         |  35 ++++++++++++++++++
 scripts/make-fixtures.sh                      |  14 +++++++
 13 files changed, 97 insertions(+)
 create mode 100644 fixtures/courses/sample/MENTOR.md
 create mode 100644 fixtures/courses/sample/code/S01 - First steps/hello.sh
 create mode 100644 fixtures/courses/sample/exercises/add/solution.js
 create mode 100644 fixtures/courses/sample/exercises/add/starter.js
 create mode 100644 fixtures/courses/sample/exercises/add/tests.js
 create mode 100644 fixtures/courses/sample/lessons/01-intro.md
 create mode 100644 fixtures/courses/sample/lessons/02-video.md
 create mode 100644 fixtures/courses/sample/lessons/03-code.md
 create mode 100644 fixtures/courses/sample/lessons/04-exercise.md
 create mode 100644 fixtures/courses/sample/media/clip.mp4
 create mode 100644 fixtures/courses/sample/media/deck.pdf
 create mode 100644 fixtures/courses/sample/stcourse.yaml
 create mode 100755 scripts/make-fixtures.sh

diff --git a/fixtures/courses/sample/MENTOR.md b/fixtures/courses/sample/MENTOR.md
new file mode 100644
index 0000000..696e9f0
--- /dev/null
+++ b/fixtures/courses/sample/MENTOR.md
@@ -0,0 +1 @@
+You are the mentor for the sample course. Give hints, never full solutions.
diff --git a/fixtures/courses/sample/code/S01 - First steps/hello.sh b/fixtures/courses/sample/code/S01 - First steps/hello.sh
new file mode 100644
index 0000000..6c02b52
--- /dev/null
+++ b/fixtures/courses/sample/code/S01 - First steps/hello.sh	
@@ -0,0 +1 @@
+echo "hello from the sample course"
diff --git a/fixtures/courses/sample/exercises/add/solution.js b/fixtures/courses/sample/exercises/add/solution.js
new file mode 100644
index 0000000..7d65831
--- /dev/null
+++ b/fixtures/courses/sample/exercises/add/solution.js
@@ -0,0 +1,3 @@
+export function add(a, b) {
+  return a + b;
+}
diff --git a/fixtures/courses/sample/exercises/add/starter.js b/fixtures/courses/sample/exercises/add/starter.js
new file mode 100644
index 0000000..29b3851
--- /dev/null
+++ b/fixtures/courses/sample/exercises/add/starter.js
@@ -0,0 +1,3 @@
+export function add(a, b) {
+  return a - b;
+}
diff --git a/fixtures/courses/sample/exercises/add/tests.js b/fixtures/courses/sample/exercises/add/tests.js
new file mode 100644
index 0000000..4d5843b
--- /dev/null
+++ b/fixtures/courses/sample/exercises/add/tests.js
@@ -0,0 +1,4 @@
+export const tests = [
+  { name: "adds 2 and 3", run: (mod, assert) => assert.equal(mod.add(2, 3), 5) },
+  { name: "adds -1 and 1", run: (mod, assert) => assert.equal(mod.add(-1, 1), 0) },
+];
diff --git a/fixtures/courses/sample/lessons/01-intro.md b/fixtures/courses/sample/lessons/01-intro.md
new file mode 100644
index 0000000..4e844ff
--- /dev/null
+++ b/fixtures/courses/sample/lessons/01-intro.md
@@ -0,0 +1,3 @@
+# Introduction
+
+Welcome to the sample course. It exists so tests have something small to load.
diff --git a/fixtures/courses/sample/lessons/02-video.md b/fixtures/courses/sample/lessons/02-video.md
new file mode 100644
index 0000000..52c1d4b
--- /dev/null
+++ b/fixtures/courses/sample/lessons/02-video.md
@@ -0,0 +1,3 @@
+# Transcript
+
+A two-second test pattern plays. Nothing is said.
diff --git a/fixtures/courses/sample/lessons/03-code.md b/fixtures/courses/sample/lessons/03-code.md
new file mode 100644
index 0000000..0a29890
--- /dev/null
+++ b/fixtures/courses/sample/lessons/03-code.md
@@ -0,0 +1,7 @@
+# Code along
+
+Run the script in the section files:
+
+```sh
+sh hello.sh
+```
diff --git a/fixtures/courses/sample/lessons/04-exercise.md b/fixtures/courses/sample/lessons/04-exercise.md
new file mode 100644
index 0000000..4e78add
--- /dev/null
+++ b/fixtures/courses/sample/lessons/04-exercise.md
@@ -0,0 +1,23 @@
+# Adding numbers
+
+Functions take values and return values.
+
+## Exercises
+
+### Exercise 2.1 — `add`
+
+Implement `add(a, b)` so that it returns the sum of its arguments.
+
+## Hints
+
+<details><summary>Exercise 2.1 (add) — nudge</summary>
+
+Which operator combines two numbers?
+
+</details>
+
+<details><summary>Exercise 2.1 (add) — near-solution</summary>
+
+Return `a + b`.
+
+</details>
diff --git a/fixtures/courses/sample/media/clip.mp4 b/fixtures/courses/sample/media/clip.mp4
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diff --git a/fixtures/courses/sample/media/deck.pdf b/fixtures/courses/sample/media/deck.pdf
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diff --git a/fixtures/courses/sample/stcourse.yaml b/fixtures/courses/sample/stcourse.yaml
new file mode 100644
index 0000000..7d25ac2
--- /dev/null
+++ b/fixtures/courses/sample/stcourse.yaml
@@ -0,0 +1,35 @@
+schema: 1
+id: sample
+title: Sample course
+pitch: A tiny self-contained course used by the test suite.
+visibility: public
+tracks:
+  - { id: js, label: JavaScript }
+mentor: MENTOR.md
+source: { kind: authored }
+decks:
+  - { id: d1, file: media/deck.pdf, attachTo: m1-video }
+modules:
+  - id: m1
+    title: First steps
+    code: { dir: "code/S01 - First steps", command: "sh hello.sh" }
+    lessons:
+      - { id: m1-intro, title: Introduction, type: text, file: lessons/01-intro.md }
+      - { id: m1-video, title: Watch the clip, type: video, file: media/clip.mp4, duration: 2, transcript: lessons/02-video.md }
+      - { id: m1-code, title: Code along, type: text, file: lessons/03-code.md }
+  - id: m2
+    title: Exercises
+    lessons:
+      - { id: m2-text, title: Adding numbers, type: text, file: lessons/04-exercise.md }
+      - id: m2-ex-add
+        title: "Exercise 2.1: add"
+        type: exercise
+        file: lessons/04-exercise.md
+        anchor: exercise-21--add
+        hints: { file: lessons/04-exercise.md, match: "Exercise 2.1 (add)" }
+        browser:
+          language: js
+          starter: exercises/add/starter.js
+          tests: exercises/add/tests.js
+          solution: exercises/add/solution.js
+        localCommand: "node --test"
diff --git a/scripts/make-fixtures.sh b/scripts/make-fixtures.sh
new file mode 100755
index 0000000..a9112ef
--- /dev/null
+++ b/scripts/make-fixtures.sh
@@ -0,0 +1,14 @@
+#!/bin/sh
+# Regenerates the binary fixtures under fixtures/courses/sample/media.
+set -eu
+cd "$(dirname "$0")/../fixtures/courses/sample/media"
+/usr/bin/ffmpeg -y -loglevel error -f lavfi -i "testsrc=duration=2:size=160x90:rate=10" \
+  -pix_fmt yuv420p -c:v libx264 -crf 35 -preset veryslow -movflags +faststart clip.mp4
+/home/user/.venvs/pdf/bin/python -I - <<'PY'
+import pymupdf
+doc = pymupdf.open()
+for i, text in enumerate(["Sample deck: title", "Sample deck: middle", "Sample deck: end"], 1):
+    page = doc.new_page(width=480, height=270)
+    page.insert_text((40, 135), text, fontsize=24)
+doc.save("deck.pdf", garbage=4, deflate=True)
+PY

From c78c7ec8d81577426d39a4904b918e8aa7cd0d24 Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 02:51:26 +0100
Subject: [PATCH 05/14] feat(course-format): markdown extraction, discovery,
 loading, repository

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 packages/contracts/src/server.ts             |   4 +-
 packages/course-format/src/index.ts          |   4 +
 packages/course-format/src/load.ts           | 208 +++++++++++++++++++
 packages/course-format/src/markdown.ts       |  66 ++++++
 packages/course-format/src/repository.ts     |  42 ++++
 packages/course-format/test/load.test.ts     | 147 +++++++++++++
 packages/course-format/test/markdown.test.ts |  89 ++++++++
 7 files changed, 558 insertions(+), 2 deletions(-)
 create mode 100644 packages/course-format/src/index.ts
 create mode 100644 packages/course-format/src/load.ts
 create mode 100644 packages/course-format/src/markdown.ts
 create mode 100644 packages/course-format/src/repository.ts
 create mode 100644 packages/course-format/test/load.test.ts
 create mode 100644 packages/course-format/test/markdown.test.ts

diff --git a/packages/contracts/src/server.ts b/packages/contracts/src/server.ts
index dbfca4a..4dfd75f 100644
--- a/packages/contracts/src/server.ts
+++ b/packages/contracts/src/server.ts
@@ -1,3 +1,4 @@
+import type { CourseRepository } from "@stc/course-format";
 export type Role = "owner" | "author" | "learner";
 export interface AuthUser { id: string; email: string; name: string; roles: Role[]; groups: string[] }
 export interface RequestContext { user: AuthUser | null; params: Record<string, string>; url: URL }
@@ -13,9 +14,8 @@ export type JobStatus = "queued" | "running" | "done" | "failed";
 export interface JobRecord { id: string; kind: string; status: JobStatus; progress: number; message: string | null; payload: unknown; result: unknown; error: string | null; createdAt: string; updatedAt: string }
 export interface JobQueue { enqueue(kind: string, payload: unknown): Promise<string>; get(id: string): Promise<JobRecord | null>; list(kind?: string): Promise<JobRecord[]> }
 export interface AuthService { userFromRequest(req: Request): Promise<AuthUser | null> }
-// Placeholders until Task 4 (@stc/db) and Task 7 (@stc/course-format) exist; switch to the real imports in Task 7.
+// Placeholder until Task 7 (@stc/db) exists.
 type Db = unknown;
-type CourseRepository = unknown;
 export interface ServerContext {
   config: AppConfig; db: Db; courses: CourseRepository;
   jobs: JobQueue; auth: AuthService;
diff --git a/packages/course-format/src/index.ts b/packages/course-format/src/index.ts
new file mode 100644
index 0000000..6424cba
--- /dev/null
+++ b/packages/course-format/src/index.ts
@@ -0,0 +1,4 @@
+export * from "./schema";
+export * from "./markdown";
+export * from "./load";
+export * from "./repository";
diff --git a/packages/course-format/src/load.ts b/packages/course-format/src/load.ts
new file mode 100644
index 0000000..b0e3c57
--- /dev/null
+++ b/packages/course-format/src/load.ts
@@ -0,0 +1,208 @@
+import { readdir, readFile, realpath } from "node:fs/promises";
+import { realpathSync } from "node:fs";
+import { basename, dirname, isAbsolute, join, relative, resolve, sep } from "node:path";
+import { extractHints, extractSection } from "./markdown";
+import { parseManifest, type Lesson, type Manifest } from "./schema";
+
+export type Diagnostic = {
+  level: "error" | "warning";
+  courseId?: string;
+  lessonId?: string;
+  path?: string;
+  message: string;
+};
+
+export interface LoadedCourse {
+  id: string;
+  manifestPath: string;
+  root: string;
+  manifest: Manifest | null;
+  status: "ok" | "error";
+  diagnostics: Diagnostic[];
+  lessonIndex: Map<string, { moduleId: string; lesson: Lesson }>;
+}
+
+const MANIFEST_NAME = "stcourse.yaml";
+const SKIP_DIRS = new Set(["node_modules", ".git"]);
+
+/**
+ * Absolute path of `rel` under `root` if its real path (symlinks followed) is inside the real root,
+ * else null. A nonexistent target is also null.
+ */
+export function resolveInside(root: string, rel: string): string | null {
+  try {
+    const realRoot = realpathSync(root);
+    const real = realpathSync(resolve(realRoot, rel));
+    return real === realRoot || real.startsWith(realRoot + sep) ? real : null;
+  } catch {
+    return null;
+  }
+}
+
+/** Finds stcourse.yaml at depth 0-2 under each dir. */
+export async function discoverManifests(courseDirs: string[]): Promise<string[]> {
+  const found: string[] = [];
+  const seen = new Set<string>();
+  async function walk(dir: string, depth: number) {
+    const candidate = join(dir, MANIFEST_NAME);
+    if (await Bun.file(candidate).exists()) {
+      if (!seen.has(candidate)) {
+        seen.add(candidate);
+        found.push(candidate);
+      }
+    }
+    if (depth >= 2) return;
+    let entries;
+    try {
+      entries = await readdir(dir, { withFileTypes: true });
+    } catch {
+      return;
+    }
+    entries.sort((a, b) => a.name.localeCompare(b.name));
+    for (const e of entries) {
+      if (e.isDirectory() && !SKIP_DIRS.has(e.name)) await walk(join(dir, e.name), depth + 1);
+    }
+  }
+  for (const d of courseDirs) await walk(resolve(d), 0);
+  return found;
+}
+
+export async function loadCourse(manifestPath: string): Promise<LoadedCourse> {
+  manifestPath = resolve(manifestPath);
+  const dir = dirname(manifestPath);
+  const diagnostics: Diagnostic[] = [];
+  const course: LoadedCourse = {
+    id: basename(dir),
+    manifestPath,
+    root: dir,
+    manifest: null,
+    status: "error",
+    diagnostics,
+    lessonIndex: new Map(),
+  };
+  const err = (message: string, extra: Partial<Diagnostic> = {}) =>
+    diagnostics.push({ level: "error", courseId: course.id, message, ...extra });
+
+  let text: string;
+  try {
+    text = await readFile(manifestPath, "utf8");
+  } catch (e) {
+    err(`cannot read manifest ${manifestPath}: ${(e as Error).message}`, { path: manifestPath });
+    return course;
+  }
+  const parsed = parseManifest(text);
+  if (!parsed.ok) {
+    for (const m of parsed.errors) err(`invalid manifest: ${m}`, { path: manifestPath });
+    return course;
+  }
+  const manifest = parsed.manifest;
+  course.manifest = manifest;
+  course.id = manifest.id;
+  course.root = resolve(dir, manifest.root ?? ".");
+  for (const mod of manifest.modules) {
+    for (const lesson of mod.lessons) course.lessonIndex.set(lesson.id, { moduleId: mod.id, lesson });
+  }
+
+  try {
+    course.root = await realpath(course.root);
+  } catch {
+    err(`course root does not exist or is unreadable: ${course.root}`, { path: course.root });
+    return course;
+  }
+  const root = course.root;
+
+  const mdCache = new Map<string, string>();
+  const readMd = async (rel: string): Promise<string | null> => {
+    const abs = resolveInside(root, rel);
+    if (!abs) return null;
+    if (!mdCache.has(abs)) mdCache.set(abs, await Bun.file(abs).text());
+    return mdCache.get(abs)!;
+  };
+  /** Reports an error and returns false when `rel` does not exist inside the root. */
+  const requireFile = (rel: string, what: string, lessonId?: string): boolean => {
+    if (resolveInside(root, rel)) return true;
+    err(`${what} not found: ${rel}`, { lessonId, path: rel });
+    return false;
+  };
+
+  if (manifest.cover) requireFile(manifest.cover, "cover", undefined);
+  if (manifest.mentor) requireFile(manifest.mentor, "mentor file", undefined);
+  for (const d of manifest.decks ?? []) requireFile(d.file, `deck "${d.id}" file`);
+  for (const a of manifest.attachments ?? []) requireFile(a.file, "attachment");
+
+  for (const mod of manifest.modules) {
+    if (mod.code) requireFile(mod.code.dir, `module "${mod.id}" code dir`);
+    for (const l of mod.lessons) {
+      const id = l.id;
+      let fileOk = true;
+      if (l.file) fileOk = requireFile(l.file, "lesson file", id);
+      if (l.transcript) requireFile(l.transcript, "transcript", id);
+      for (const [track, t] of Object.entries(l.tracks ?? {})) {
+        if (t.file) requireFile(t.file, `track "${track}" file`, id);
+      }
+      if (l.browser) {
+        requireFile(l.browser.starter, "browser starter", id);
+        requireFile(l.browser.tests, "browser tests", id);
+        if (l.browser.solution) requireFile(l.browser.solution, "browser solution", id);
+      }
+      if (l.anchor) {
+        const file = l.file ?? l.hints?.file;
+        if (!file) {
+          err(`anchor "${l.anchor}" given but the lesson has no file`, { lessonId: id });
+        } else if (fileOk) {
+          const md = await readMd(file);
+          if (md !== null && extractSection(md, l.anchor) === null) {
+            err(`anchor "${l.anchor}" not found in ${file}`, { lessonId: id, path: file });
+          }
+        }
+      }
+      if (l.hints) {
+        if (requireFile(l.hints.file, "hints file", id)) {
+          const md = await readMd(l.hints.file);
+          if (md !== null && extractHints(md, l.hints.match).length === 0) {
+            err(`no hint blocks matching "${l.hints.match}" in ${l.hints.file}`, { lessonId: id, path: l.hints.file });
+          }
+        }
+      }
+    }
+  }
+
+  course.status = diagnostics.some((d) => d.level === "error") ? "error" : "ok";
+  return course;
+}
+
+function isOverlay(c: LoadedCourse): boolean {
+  if (!c.manifest?.root) return false;
+  const rel = relative(dirname(c.manifestPath), resolve(dirname(c.manifestPath), c.manifest.root));
+  return rel === ".." || rel.startsWith(".." + sep) || isAbsolute(rel);
+}
+
+/** Loads every manifest found under courseDirs. Duplicate ids: the overlay wins (spec section 13). */
+export async function loadAll(courseDirs: string[]): Promise<LoadedCourse[]> {
+  const paths = await discoverManifests(courseDirs);
+  const loaded = await Promise.all(paths.map((p) => loadCourse(p)));
+  const winners = new Map<string, LoadedCourse>();
+  const result: LoadedCourse[] = [];
+  const dropped = new Set<LoadedCourse>();
+  for (const c of loaded) {
+    if (!c.manifest) {
+      result.push(c);
+      continue;
+    }
+    const prev = winners.get(c.id);
+    if (!prev) {
+      winners.set(c.id, c);
+      continue;
+    }
+    const [win, lose] = isOverlay(c) && !isOverlay(prev) ? [c, prev] : [prev, c];
+    win.diagnostics.push({
+      level: "warning",
+      courseId: win.id,
+      path: lose.manifestPath,
+      message: `shadows another manifest with the same id "${win.id}": ${lose.manifestPath}`,
+    });
+    dropped.add(lose);
+    winners.set(c.id, win);
+  }
+  return loaded.filter((c) => !dropped.has(c));
+}
diff --git a/packages/course-format/src/markdown.ts b/packages/course-format/src/markdown.ts
new file mode 100644
index 0000000..512e636
--- /dev/null
+++ b/packages/course-format/src/markdown.ts
@@ -0,0 +1,66 @@
+/** GitHub-style heading slug: lowercase, markdown stripped, punctuation dropped, spaces to hyphens. */
+export function slugify(heading: string): string {
+  return heading
+    .replace(/!?\[([^\]]*)\]\([^)]*\)/g, "$1") // links and images keep their text
+    .replace(/[`*~]/g, "") // code spans and emphasis markers
+    .replace(/<[^>]+>/g, "") // inline html
+    .trim()
+    .toLowerCase()
+    .replace(/[^\p{L}\p{N}\p{M}\s_-]/gu, "")
+    .replace(/\s/g, "-");
+}
+
+interface Heading {
+  line: number;
+  level: number;
+  text: string;
+}
+
+function headings(lines: string[]): Heading[] {
+  const out: Heading[] = [];
+  let fence: string | null = null;
+  lines.forEach((line, i) => {
+    const f = /^ {0,3}(`{3,}|~{3,})/.exec(line);
+    if (f) {
+      const marker = f[1]![0]!;
+      if (fence === null) fence = marker;
+      else if (fence === marker) fence = null;
+      return;
+    }
+    if (fence !== null) return;
+    const h = /^ {0,3}(#{1,6})\s+(.*?)\s*#*\s*$/.exec(line);
+    if (h) out.push({ line: i, level: h[1]!.length, text: h[2]! });
+  });
+  return out;
+}
+
+/** Heading line plus everything up to the next heading of the same or a higher level. */
+export function extractSection(markdown: string, anchor: string): string | null {
+  const lines = markdown.split(/\r?\n/);
+  const hs = headings(lines);
+  const seen = new Map<string, number>();
+  for (let i = 0; i < hs.length; i++) {
+    const h = hs[i]!;
+    const base = slugify(h.text);
+    const n = seen.get(base) ?? 0;
+    seen.set(base, n + 1);
+    const slug = n === 0 ? base : `${base}-${n}`; // GitHub numbers duplicates
+    if (slug !== anchor) continue;
+    const next = hs.slice(i + 1).find((x) => x.level <= h.level);
+    return lines.slice(h.line, next ? next.line : lines.length).join("\n").trimEnd();
+  }
+  return null;
+}
+
+/** `<details><summary>…</summary>…</details>` blocks whose summary starts with `match`, in document order. */
+export function extractHints(markdown: string, match: string): { label: string; body: string }[] {
+  const out: { label: string; body: string }[] = [];
+  const re = /<details>\s*<summary>([\s\S]*?)<\/summary>([\s\S]*?)<\/details>/g;
+  for (const m of markdown.matchAll(re)) {
+    const summary = m[1]!.trim();
+    if (!summary.startsWith(match)) continue;
+    const label = summary.slice(match.length).replace(/^\s*(?:—|-|\()\s*/, "").trim();
+    out.push({ label, body: m[2]!.trim() });
+  }
+  return out;
+}
diff --git a/packages/course-format/src/repository.ts b/packages/course-format/src/repository.ts
new file mode 100644
index 0000000..72060b5
--- /dev/null
+++ b/packages/course-format/src/repository.ts
@@ -0,0 +1,42 @@
+import { extname } from "node:path";
+import { loadAll, resolveInside, type LoadedCourse } from "./load";
+import { extractSection } from "./markdown";
+
+export interface CourseRepository {
+  list(): LoadedCourse[];
+  get(id: string): LoadedCourse | null;
+  /** Re-scans the course dirs. `id` is accepted for API symmetry; a rescan is cheap and keeps overlay shadowing correct. */
+  reload(id?: string): Promise<void>;
+  readLessonMarkdown(courseId: string, lessonId: string): Promise<string | null>;
+  /** Absolute real path if inside the course root (symlinks followed), else null. */
+  resolvePath(courseId: string, relPath: string): string | null;
+}
+
+const MD = new Set([".md", ".markdown"]);
+
+export async function createCourseRepository(courseDirs: string[]): Promise<CourseRepository> {
+  let courses = await loadAll(courseDirs);
+  const repo: CourseRepository = {
+    list: () => courses,
+    get: (id) => courses.find((c) => c.id === id) ?? null,
+    async reload() {
+      courses = await loadAll(courseDirs);
+    },
+    async readLessonMarkdown(courseId, lessonId) {
+      const entry = repo.get(courseId)?.lessonIndex.get(lessonId);
+      if (!entry) return null;
+      const { lesson } = entry;
+      const rel = lesson.type === "video" ? lesson.transcript : lesson.file;
+      if (!rel || !MD.has(extname(rel).toLowerCase())) return null;
+      const abs = repo.resolvePath(courseId, rel);
+      if (!abs) return null;
+      const text = await Bun.file(abs).text();
+      return lesson.anchor ? extractSection(text, lesson.anchor) : text;
+    },
+    resolvePath(courseId, relPath) {
+      const c = repo.get(courseId);
+      return c ? resolveInside(c.root, relPath) : null;
+    },
+  };
+  return repo;
+}
diff --git a/packages/course-format/test/load.test.ts b/packages/course-format/test/load.test.ts
new file mode 100644
index 0000000..a93f3d3
--- /dev/null
+++ b/packages/course-format/test/load.test.ts
@@ -0,0 +1,147 @@
+import { afterAll, describe, expect, test } from "bun:test";
+import { mkdtemp, rm, symlink } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join, resolve } from "node:path";
+import { createCourseRepository, discoverManifests, loadAll, loadCourse } from "../src/index";
+
+const sampleDir = resolve(import.meta.dir, "../../../fixtures/courses/sample");
+const tmps: string[] = [];
+async function tmp(): Promise<string> {
+  const d = await mkdtemp(join(tmpdir(), "stc-"));
+  tmps.push(d);
+  return d;
+}
+afterAll(() => Promise.all(tmps.map((d) => rm(d, { recursive: true, force: true }))));
+
+const manifest = (id: string, extra: string, lessons: string) =>
+  `schema: 1\nid: ${id}\ntitle: T\n${extra}modules:\n  - id: m\n    title: M\n    lessons:\n${lessons}\n`;
+
+describe("sample fixture", () => {
+  test("loads the sample fixture with no errors", async () => {
+    const c = await loadCourse(join(sampleDir, "stcourse.yaml"));
+    expect(c.diagnostics).toEqual([]);
+    expect(c.status).toBe("ok");
+    expect(c.id).toBe("sample");
+    expect([...c.lessonIndex.keys()]).toEqual(["m1-intro", "m1-video", "m1-code", "m2-text", "m2-ex-add"]);
+  });
+
+  test("repository reads lesson markdown and sections", async () => {
+    const repo = await createCourseRepository([sampleDir]);
+    expect(repo.list().map((c) => c.id)).toEqual(["sample"]);
+    expect(await repo.readLessonMarkdown("sample", "m1-intro")).toContain("# Introduction");
+    const ex = await repo.readLessonMarkdown("sample", "m2-ex-add");
+    expect(ex!.startsWith("### Exercise 2.1")).toBe(true);
+    expect(await repo.readLessonMarkdown("sample", "nope")).toBeNull();
+    expect(repo.get("nope")).toBeNull();
+  });
+});
+
+describe("discovery", () => {
+  test("finds manifests at depth 0 to 2 only", async () => {
+    const d = await tmp();
+    for (const p of ["stcourse.yaml", "a/stcourse.yaml", "a/b/stcourse.yaml", "a/b/c/stcourse.yaml"]) {
+      await Bun.write(join(d, p), "x");
+    }
+    const found = (await discoverManifests([d])).map((p) => p.slice(d.length + 1));
+    expect(found.sort()).toEqual(["a/b/stcourse.yaml", "a/stcourse.yaml", "stcourse.yaml"]);
+  });
+});
+
+describe("overlays and errors", () => {
+  test("overlay with missing root gives status error", async () => {
+    const d = await tmp();
+    const missing = join(d, "gone-repo");
+    await Bun.write(join(d, "overlay/stcourse.yaml"), manifest("broken", `root: ${missing}\n`, "      - { id: l, title: L, type: text, file: a.md }"));
+    await Bun.write(join(d, "ok/a.md"), "# A\n");
+    await Bun.write(join(d, "ok/stcourse.yaml"), manifest("fine", "", "      - { id: l, title: L, type: text, file: a.md }"));
+    const all = await loadAll([d]);
+    expect(all.map((c) => c.id).sort()).toEqual(["broken", "fine"]);
+    const broken = all.find((c) => c.id === "broken")!;
+    expect(broken.status).toBe("error");
+    expect(broken.diagnostics.some((x) => x.level === "error" && x.message.includes(missing))).toBe(true);
+    expect(all.find((c) => c.id === "fine")!.status).toBe("ok");
+  });
+
+  test("missing lesson file, anchor and hints each produce one error diagnostic naming lessonId", async () => {
+    const d = await tmp();
+    await Bun.write(join(d, "a.md"), "# A\n\n## Real\n\ntext\n");
+    const lessons = [
+      "      - { id: no-file, title: L, type: text, file: missing.md }",
+      "      - { id: no-anchor, title: L, type: text, file: a.md, anchor: ghost }",
+      "      - { id: no-hints, title: L, type: exercise, file: a.md, anchor: real, hints: { file: a.md, match: 'Exercise 1' } }",
+    ].join("\n");
+    await Bun.write(join(d, "stcourse.yaml"), manifest("bad", "", lessons));
+    const c = await loadCourse(join(d, "stcourse.yaml"));
+    expect(c.status).toBe("error");
+    const errs = c.diagnostics.filter((x) => x.level === "error");
+    expect(errs.map((e) => e.lessonId)).toEqual(["no-file", "no-anchor", "no-hints"]);
+    expect(errs[0]!.path).toBe("missing.md");
+    expect(errs[1]!.message).toContain("ghost");
+    expect(errs[2]!.message).toContain("Exercise 1");
+  });
+
+  test("invalid manifest gives an error course and does not throw", async () => {
+    const d = await tmp();
+    await Bun.write(join(d, "stcourse.yaml"), "schema: 2\nid: x\n");
+    const c = await loadCourse(join(d, "stcourse.yaml"));
+    expect(c.status).toBe("error");
+    expect(c.manifest).toBeNull();
+    expect(c.diagnostics.length).toBeGreaterThan(0);
+  });
+
+  test("handles spaces and unicode in paths", async () => {
+    const d = await tmp();
+    const rel = "S08 - Containerizing Applications/Æble notes.md";
+    await Bun.write(join(d, rel), "# Æble\n");
+    await Bun.write(join(d, "stcourse.yaml"), manifest("uni", "", `      - { id: l, title: L, type: text, file: "${rel}" }`));
+    const repo = await createCourseRepository([d]);
+    expect(repo.get("uni")!.status).toBe("ok");
+    expect(await repo.readLessonMarkdown("uni", "l")).toBe("# Æble\n");
+    expect(repo.resolvePath("uni", rel)).toContain("Æble notes.md");
+  });
+
+  test("overlay wins over in-repo manifest with same id", async () => {
+    const d = await tmp();
+    const lesson = "      - { id: l, title: L, type: text, file: a.md }";
+    await Bun.write(join(d, "repo/a.md"), "# A\n");
+    await Bun.write(join(d, "repo/stcourse.yaml"), manifest("dup", "", lesson.replace("L,", "InRepo,")));
+    await Bun.write(join(d, "overlays/dup/stcourse.yaml"), manifest("dup", `root: ${join(d, "repo")}\n`, lesson.replace("L,", "Overlay,")));
+    const all = await loadAll([d]);
+    const dup = all.filter((c) => c.id === "dup");
+    expect(dup).toHaveLength(1);
+    expect(dup[0]!.manifestPath).toBe(join(d, "overlays/dup/stcourse.yaml"));
+    const warn = dup[0]!.diagnostics.find((x) => x.level === "warning");
+    expect(warn!.path).toBe(join(d, "repo/stcourse.yaml"));
+  });
+
+  test("overlay wins regardless of discovery order", async () => {
+    const d = await tmp();
+    const lesson = "      - { id: l, title: L, type: text, file: a.md }";
+    await Bun.write(join(d, "a-repo/a.md"), "# A\n");
+    await Bun.write(join(d, "a-repo/stcourse.yaml"), manifest("dup", "", lesson));
+    await Bun.write(join(d, "z-overlay/stcourse.yaml"), manifest("dup", `root: ${join(d, "a-repo")}\n`, lesson));
+    const all = await loadAll([d]);
+    expect(all).toHaveLength(1);
+    expect(all[0]!.manifestPath).toBe(join(d, "z-overlay/stcourse.yaml"));
+  });
+});
+
+describe("resolvePath", () => {
+  test("rejects ../, absolute paths and symlink escape", async () => {
+    const d = await tmp();
+    await Bun.write(join(d, "root/a.md"), "# A\n");
+    await Bun.write(join(d, "outside.txt"), "secret");
+    await symlink("/etc", join(d, "root/etc-link"));
+    await symlink(join(d, "outside.txt"), join(d, "root/out-link.txt"));
+    await Bun.write(join(d, "root/stcourse.yaml"), manifest("r", "", "      - { id: l, title: L, type: text, file: a.md }"));
+    const repo = await createCourseRepository([join(d, "root")]);
+    expect(repo.resolvePath("r", "a.md")).not.toBeNull();
+    expect(repo.resolvePath("r", "../outside.txt")).toBeNull();
+    expect(repo.resolvePath("r", join(d, "outside.txt"))).toBeNull();
+    expect(repo.resolvePath("r", "etc-link/passwd")).toBeNull();
+    expect(repo.resolvePath("r", "etc-link")).toBeNull();
+    expect(repo.resolvePath("r", "out-link.txt")).toBeNull();
+    expect(repo.resolvePath("r", "missing.md")).toBeNull();
+    expect(repo.resolvePath("nope", "a.md")).toBeNull();
+  });
+});
diff --git a/packages/course-format/test/markdown.test.ts b/packages/course-format/test/markdown.test.ts
new file mode 100644
index 0000000..888d53d
--- /dev/null
+++ b/packages/course-format/test/markdown.test.ts
@@ -0,0 +1,89 @@
+import { describe, expect, test } from "bun:test";
+import { extractHints, extractSection, slugify } from "../src/markdown";
+
+describe("slugify", () => {
+  test("follows GitHub's algorithm", () => {
+    expect(slugify("Exercise 3.1 — `move`")).toBe("exercise-31--move");
+    expect(slugify("Why this module")).toBe("why-this-module");
+    expect(slugify("Rules as functions `State → State`")).toBe("rules-as-functions-state--state");
+    expect(slugify("**Bold** and [a link](http://x.y)")).toBe("bold-and-a-link");
+  });
+});
+
+const sample = `# Top
+
+intro
+
+## First
+
+one
+
+### Middle
+
+middle body
+
+\`\`\`sh
+# not a heading
+\`\`\`
+
+#### Deeper
+
+deep body
+
+### Sibling
+
+sibling body
+
+## Last
+
+end
+`;
+
+describe("extractSection", () => {
+  test("returns only the middle section, including deeper headings", () => {
+    const s = extractSection(sample, "middle");
+    expect(s).not.toBeNull();
+    expect(s!.startsWith("### Middle")).toBe(true);
+    expect(s).toContain("# not a heading");
+    expect(s).toContain("deep body");
+    expect(s).not.toContain("sibling body");
+    expect(s).not.toContain("one");
+  });
+  test("returns null for an unknown anchor", () => {
+    expect(extractSection(sample, "nope")).toBeNull();
+  });
+  test("a section runs to the end of file when nothing follows", () => {
+    expect(extractSection(sample, "last")).toBe("## Last\n\nend");
+  });
+});
+
+describe("extractHints", () => {
+  const md = `## Hints
+
+<details><summary>Exercise 3.1 (move) — nudge</summary>
+
+Think about direction.
+
+</details>
+
+<details><summary>Exercise 3.1 (move) — stronger hint</summary>
+
+Add the delta.
+
+</details>
+
+<details><summary>Exercise 3.2 (inBounds) — nudge</summary>
+
+Other.
+
+</details>
+`;
+  test("returns matching blocks in order with trimmed labels", () => {
+    const h = extractHints(md, "Exercise 3.1 (move)");
+    expect(h.map((x) => x.label)).toEqual(["nudge", "stronger hint"]);
+    expect(h[0]!.body).toBe("Think about direction.");
+  });
+  test("returns [] when nothing matches", () => {
+    expect(extractHints(md, "Exercise 9.9")).toEqual([]);
+  });
+});

From b8c65626f9096ccc6e04327d84f91ba5a83a52c7 Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 02:52:24 +0100
Subject: [PATCH 06/14] feat: overlay manifests for the two reference courses

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 overlays/pure-snake/stcourse.yaml             | 558 ++++++++++++++++++
 overlays/systemic-design/stcourse.yaml        | 110 ++++
 packages/course-format/test/reference.test.ts |  32 +
 3 files changed, 700 insertions(+)
 create mode 100644 overlays/pure-snake/stcourse.yaml
 create mode 100644 overlays/systemic-design/stcourse.yaml
 create mode 100644 packages/course-format/test/reference.test.ts

diff --git a/overlays/pure-snake/stcourse.yaml b/overlays/pure-snake/stcourse.yaml
new file mode 100644
index 0000000..9f22b99
--- /dev/null
+++ b/overlays/pure-snake/stcourse.yaml
@@ -0,0 +1,558 @@
+schema: 1
+id: pure-snake
+title: Pure Snake
+pitch: Build Snake as pure functions, then wire it to the world with IO and event streams, in JavaScript, Scala 3 or F#.
+visibility: public
+root: /home/user/functional-programming-course
+tracks:
+  - { id: js, label: JavaScript }
+  - { id: scala, label: Scala 3 }
+  - { id: fsharp, label: F# }
+mentor: MENTOR.md
+source: { kind: authored }
+modules:
+  - id: m00
+    title: "Setup and how to use this course"
+    lessons:
+      - { id: m00-text, title: "Setup and how to use this course", type: text, file: "course/00-setup.md" }
+      - id: m00-ex-green-lights
+        title: "Exercise 0.1 — Green lights"
+        type: exercise
+        file: "course/00-setup.md"
+        anchor: exercise-01--green-lights
+        hints: { file: "course/00-setup.md", match: "Exercise 0.1" }
+        localCommand:
+          js: "cd js && node --test \"test/m00-*.test.js\""
+          scala: "cd scala && ./test.sh M00"
+          fsharp: "cd fsharp && ./test.sh M00"
+      - id: m00-ex-read-a-red-test
+        title: "Exercise 0.2 — Read a red test"
+        type: exercise
+        file: "course/00-setup.md"
+        anchor: exercise-02--read-a-red-test
+        hints: { file: "course/00-setup.md", match: "Exercise 0.2" }
+        localCommand:
+          js: "cd js && node --test \"test/m00-*.test.js\""
+          scala: "cd scala && ./test.sh M00"
+          fsharp: "cd fsharp && ./test.sh M00"
+      - id: m00-ex-break-the-purity-audit-on-purpose
+        title: "Exercise 0.3 — Break the purity audit on purpose"
+        type: exercise
+        file: "course/00-setup.md"
+        anchor: exercise-03--break-the-purity-audit-on-purpose
+        localCommand:
+          js: "cd js && node --test \"test/m00-*.test.js\""
+          scala: "cd scala && ./test.sh M00"
+          fsharp: "cd fsharp && ./test.sh M00"
+  - id: m01
+    title: "Purity and immutability"
+    lessons:
+      - { id: m01-text, title: "Purity and immutability", type: text, file: "course/01-purity-and-immutability.md" }
+      - id: m01-ex-range
+        title: "Exercise 1.1 — `range`"
+        type: exercise
+        file: "course/01-purity-and-immutability.md"
+        anchor: exercise-11--range
+        hints: { file: "course/01-purity-and-immutability.md", match: "Exercise 1.1 (range)" }
+        localCommand:
+          js: "cd js && node --test \"test/m01-*.test.js\""
+          scala: "cd scala && ./test.sh M01"
+          fsharp: "cd fsharp && ./test.sh M01"
+      - id: m01-ex-droplast
+        title: "Exercise 1.2 — `dropLast`"
+        type: exercise
+        file: "course/01-purity-and-immutability.md"
+        anchor: exercise-12--droplast
+        hints: { file: "course/01-purity-and-immutability.md", match: "Exercise 1.2 (dropLast)" }
+        localCommand:
+          js: "cd js && node --test \"test/m01-*.test.js\""
+          scala: "cd scala && ./test.sh M01"
+          fsharp: "cd fsharp && ./test.sh M01"
+      - id: m01-ex-contains
+        title: "Exercise 1.3 — `contains`"
+        type: exercise
+        file: "course/01-purity-and-immutability.md"
+        anchor: exercise-13--contains
+        hints: { file: "course/01-purity-and-immutability.md", match: "Exercise 1.3 (contains)" }
+        localCommand:
+          js: "cd js && node --test \"test/m01-*.test.js\""
+          scala: "cd scala && ./test.sh M01"
+          fsharp: "cd fsharp && ./test.sh M01"
+      - id: m01-ex-pipe
+        title: "Exercise 1.4 — `pipe` (JS only)"
+        type: exercise
+        file: "course/01-purity-and-immutability.md"
+        anchor: exercise-14--pipe-js-only
+        hints: { file: "course/01-purity-and-immutability.md", match: "Exercise 1.4 (pipe)" }
+        localCommand:
+          js: "cd js && node --test \"test/m01-*.test.js\""
+          scala: "cd scala && ./test.sh M01"
+          fsharp: "cd fsharp && ./test.sh M01"
+      - id: m01-ex-compose
+        title: "Exercise 1.5 — `compose` (JS only)"
+        type: exercise
+        file: "course/01-purity-and-immutability.md"
+        anchor: exercise-15--compose-js-only
+        hints: { file: "course/01-purity-and-immutability.md", match: "Exercise 1.5 (compose)" }
+        localCommand:
+          js: "cd js && node --test \"test/m01-*.test.js\""
+          scala: "cd scala && ./test.sh M01"
+          fsharp: "cd fsharp && ./test.sh M01"
+      - id: m01-ex-deepfreeze
+        title: "Exercise 1.6 — `deepFreeze` (JS only)"
+        type: exercise
+        file: "course/01-purity-and-immutability.md"
+        anchor: exercise-16--deepfreeze-js-only
+        hints: { file: "course/01-purity-and-immutability.md", match: "Exercise 1.6 (deepFreeze)" }
+        localCommand:
+          js: "cd js && node --test \"test/m01-*.test.js\""
+          scala: "cd scala && ./test.sh M01"
+          fsharp: "cd fsharp && ./test.sh M01"
+  - id: m02
+    title: "The game as data"
+    lessons:
+      - { id: m02-text, title: "The game as data", type: text, file: "course/02-the-game-as-data.md" }
+      - id: m02-ex-your-own-design
+        title: "Exercise 2.0 — Your own design (paper)"
+        type: exercise
+        file: "course/02-the-game-as-data.md"
+        anchor: exercise-20--your-own-design-paper
+        localCommand:
+          js: "cd js && node --test \"test/m02-*.test.js\""
+          scala: "cd scala && ./test.sh M02"
+          fsharp: "cd fsharp && ./test.sh M02"
+      - id: m02-ex-point
+        title: "Exercise 2.1 — `point` and `pointEquals` (JS)"
+        type: exercise
+        file: "course/02-the-game-as-data.md"
+        anchor: exercise-21--point-and-pointequals-js
+        hints: { file: "course/02-the-game-as-data.md", match: "Exercise 2.1 (pointEquals)" }
+        localCommand:
+          js: "cd js && node --test \"test/m02-*.test.js\""
+          scala: "cd scala && ./test.sh M02"
+          fsharp: "cd fsharp && ./test.sh M02"
+      - id: m02-ex-delta
+        title: "Exercise 2.2 — `delta`"
+        type: exercise
+        file: "course/02-the-game-as-data.md"
+        anchor: exercise-22--delta
+        hints: { file: "course/02-the-game-as-data.md", match: "Exercises 2.2 and 2.3 (delta, opposite)" }
+        localCommand:
+          js: "cd js && node --test \"test/m02-*.test.js\""
+          scala: "cd scala && ./test.sh M02"
+          fsharp: "cd fsharp && ./test.sh M02"
+      - id: m02-ex-opposite
+        title: "Exercise 2.3 — `opposite`"
+        type: exercise
+        file: "course/02-the-game-as-data.md"
+        anchor: exercise-23--opposite
+        hints: { file: "course/02-the-game-as-data.md", match: "Exercises 2.2 and 2.3 (delta, opposite)" }
+        localCommand:
+          js: "cd js && node --test \"test/m02-*.test.js\""
+          scala: "cd scala && ./test.sh M02"
+          fsharp: "cd fsharp && ./test.sh M02"
+      - id: m02-ex-action
+        title: "Exercise 2.4 — `Action` (JS)"
+        type: exercise
+        file: "course/02-the-game-as-data.md"
+        anchor: exercise-24--action-js
+        hints: { file: "course/02-the-game-as-data.md", match: "Exercise 2.4 (Action)" }
+        localCommand:
+          js: "cd js && node --test \"test/m02-*.test.js\""
+          scala: "cd scala && ./test.sh M02"
+          fsharp: "cd fsharp && ./test.sh M02"
+      - id: m02-ex-initialstate
+        title: "Exercise 2.5 — `initialState`"
+        type: exercise
+        file: "course/02-the-game-as-data.md"
+        anchor: exercise-25--initialstate
+        hints: { file: "course/02-the-game-as-data.md", match: "Exercise 2.5 (initialState)" }
+        localCommand:
+          js: "cd js && node --test \"test/m02-*.test.js\""
+          scala: "cd scala && ./test.sh M02"
+          fsharp: "cd fsharp && ./test.sh M02"
+  - id: m03
+    title: "Pure game rules"
+    lessons:
+      - { id: m03-text, title: "Pure game rules", type: text, file: "course/03-pure-game-rules.md" }
+      - id: m03-ex-move
+        title: "Exercise 3.1 — `move`"
+        type: exercise
+        file: "course/03-pure-game-rules.md"
+        anchor: exercise-31--move
+        hints: { file: "course/03-pure-game-rules.md", match: "Exercise 3.1 (move)" }
+        localCommand:
+          js: "cd js && node --test \"test/m03-*.test.js\""
+          scala: "cd scala && ./test.sh M03"
+          fsharp: "cd fsharp && ./test.sh M03"
+      - id: m03-ex-inbounds
+        title: "Exercise 3.2 — `inBounds`"
+        type: exercise
+        file: "course/03-pure-game-rules.md"
+        anchor: exercise-32--inbounds
+        hints: { file: "course/03-pure-game-rules.md", match: "Exercise 3.2 (inBounds)" }
+        localCommand:
+          js: "cd js && node --test \"test/m03-*.test.js\""
+          scala: "cd scala && ./test.sh M03"
+          fsharp: "cd fsharp && ./test.sh M03"
+      - id: m03-ex-turn
+        title: "Exercise 3.3 — `turn`"
+        type: exercise
+        file: "course/03-pure-game-rules.md"
+        anchor: exercise-33--turn
+        hints: { file: "course/03-pure-game-rules.md", match: "Exercise 3.3 (turn)" }
+        localCommand:
+          js: "cd js && node --test \"test/m03-*.test.js\""
+          scala: "cd scala && ./test.sh M03"
+          fsharp: "cd fsharp && ./test.sh M03"
+      - id: m03-ex-advance
+        title: "Exercise 3.4 — `advance`"
+        type: exercise
+        file: "course/03-pure-game-rules.md"
+        anchor: exercise-34--advance
+        hints: { file: "course/03-pure-game-rules.md", match: "Exercise 3.4 (advance)" }
+        localCommand:
+          js: "cd js && node --test \"test/m03-*.test.js\""
+          scala: "cd scala && ./test.sh M03"
+          fsharp: "cd fsharp && ./test.sh M03"
+  - id: m04
+    title: "Randomness without side effects"
+    lessons:
+      - { id: m04-text, title: "Randomness without side effects", type: text, file: "course/04-randomness-without-side-effects.md" }
+      - id: m04-ex-nextuint32
+        title: "Exercise 4.1 — `nextUint32`"
+        type: exercise
+        file: "course/04-randomness-without-side-effects.md"
+        anchor: exercise-41--nextuint32
+        hints: { file: "course/04-randomness-without-side-effects.md", match: "Exercise 4.1 (nextUint32)" }
+        localCommand:
+          js: "cd js && node --test \"test/m04-*.test.js\""
+          scala: "cd scala && ./test.sh M04"
+          fsharp: "cd fsharp && ./test.sh M04"
+      - id: m04-ex-pure
+        title: "Exercise 4.2 — `pure`, `map`, `flatMap`, `run`"
+        type: exercise
+        file: "course/04-randomness-without-side-effects.md"
+        anchor: exercise-42--pure-map-flatmap-run
+        hints: { file: "course/04-randomness-without-side-effects.md", match: "Exercise 4.2 (pure, map, flatMap, run)" }
+        localCommand:
+          js: "cd js && node --test \"test/m04-*.test.js\""
+          scala: "cd scala && ./test.sh M04"
+          fsharp: "cd fsharp && ./test.sh M04"
+      - id: m04-ex-intbelow
+        title: "Exercise 4.3 — `intBelow`"
+        type: exercise
+        file: "course/04-randomness-without-side-effects.md"
+        anchor: exercise-43--intbelow
+        hints: { file: "course/04-randomness-without-side-effects.md", match: "Exercise 4.3 (intBelow)" }
+        localCommand:
+          js: "cd js && node --test \"test/m04-*.test.js\""
+          scala: "cd scala && ./test.sh M04"
+          fsharp: "cd fsharp && ./test.sh M04"
+      - id: m04-ex-freecells
+        title: "Exercise 4.4 — `freeCells`"
+        type: exercise
+        file: "course/04-randomness-without-side-effects.md"
+        anchor: exercise-44--freecells
+        hints: { file: "course/04-randomness-without-side-effects.md", match: "Exercise 4.4 (freeCells)" }
+        localCommand:
+          js: "cd js && node --test \"test/m04-*.test.js\""
+          scala: "cd scala && ./test.sh M04"
+          fsharp: "cd fsharp && ./test.sh M04"
+      - id: m04-ex-spawnapple
+        title: "Exercise 4.5 — `spawnApple`"
+        type: exercise
+        file: "course/04-randomness-without-side-effects.md"
+        anchor: exercise-45--spawnapple
+        hints: { file: "course/04-randomness-without-side-effects.md", match: "Exercise 4.5 (spawnApple)" }
+        localCommand:
+          js: "cd js && node --test \"test/m04-*.test.js\""
+          scala: "cd scala && ./test.sh M04"
+          fsharp: "cd fsharp && ./test.sh M04"
+      - id: m04-ex-tick
+        title: "Exercise 4.6 — `tick` and `newGame`"
+        type: exercise
+        file: "course/04-randomness-without-side-effects.md"
+        anchor: exercise-46--tick-and-newgame
+        hints: { file: "course/04-randomness-without-side-effects.md", match: "Exercise 4.6 (tick, newGame)" }
+        localCommand:
+          js: "cd js && node --test \"test/m04-*.test.js\""
+          scala: "cd scala && ./test.sh M04"
+          fsharp: "cd fsharp && ./test.sh M04"
+  - id: m05
+    title: "Folding time"
+    lessons:
+      - { id: m05-text, title: "Folding time", type: text, file: "course/05-folding-time.md" }
+      - id: m05-ex-update
+        title: "Exercise 5.1 — `update`"
+        type: exercise
+        file: "course/05-folding-time.md"
+        anchor: exercise-51--update
+        hints: { file: "course/05-folding-time.md", match: "Exercise 5.1 (update)" }
+        localCommand:
+          js: "cd js && node --test \"test/m05-*.test.js\""
+          scala: "cd scala && ./test.sh M05"
+          fsharp: "cd fsharp && ./test.sh M05"
+      - id: m05-ex-replay
+        title: "Exercise 5.2 — `replay`"
+        type: exercise
+        file: "course/05-folding-time.md"
+        anchor: exercise-52--replay
+        hints: { file: "course/05-folding-time.md", match: "Exercise 5.2 (replay)" }
+        localCommand:
+          js: "cd js && node --test \"test/m05-*.test.js\""
+          scala: "cd scala && ./test.sh M05"
+          fsharp: "cd fsharp && ./test.sh M05"
+      - id: m05-ex-history
+        title: "Exercise 5.3 — `history`"
+        type: exercise
+        file: "course/05-folding-time.md"
+        anchor: exercise-53--history
+        hints: { file: "course/05-folding-time.md", match: "Exercise 5.3 (history)" }
+        localCommand:
+          js: "cd js && node --test \"test/m05-*.test.js\""
+          scala: "cd scala && ./test.sh M05"
+          fsharp: "cd fsharp && ./test.sh M05"
+  - id: m06
+    title: "Rendering as data"
+    lessons:
+      - { id: m06-text, title: "Rendering as data", type: text, file: "course/06-rendering-as-data.md" }
+      - id: m06-ex-view
+        title: "Exercise 6.1 — `view`"
+        type: exercise
+        file: "course/06-rendering-as-data.md"
+        anchor: exercise-61--view
+        hints: { file: "course/06-rendering-as-data.md", match: "Exercise 6.1" }
+        localCommand:
+          js: "cd js && node --test \"test/m06-*.test.js\""
+          scala: "cd scala && ./test.sh M06"
+          fsharp: "cd fsharp && ./test.sh M06"
+      - id: m06-ex-a-second-interpreter
+        title: "Exercise 6.2 (optional, untested) — a second interpreter"
+        type: exercise
+        file: "course/06-rendering-as-data.md"
+        anchor: exercise-62-optional-untested--a-second-interpreter
+        localCommand:
+          js: "cd js && node --test \"test/m06-*.test.js\""
+          scala: "cd scala && ./test.sh M06"
+          fsharp: "cd fsharp && ./test.sh M06"
+  - id: m07
+    title: "The IO type"
+    lessons:
+      - { id: m07-text, title: "The IO type", type: text, file: "course/07-the-io-type.md" }
+      - id: m07-ex-pure
+        title: "Exercise 7.1 — `pure` and `effect`"
+        type: exercise
+        file: "course/07-the-io-type.md"
+        anchor: exercise-71--pure-and-effect
+        hints: { file: "course/07-the-io-type.md", match: "Exercise 7.1" }
+        localCommand:
+          js: "cd js && node --test \"test/m07-*.test.js\""
+          scala: "cd scala && ./test.sh M07"
+          fsharp: "cd fsharp && ./test.sh M07"
+      - id: m07-ex-map
+        title: "Exercise 7.2 — `map` and `flatMap`"
+        type: exercise
+        file: "course/07-the-io-type.md"
+        anchor: exercise-72--map-and-flatmap
+        hints: { file: "course/07-the-io-type.md", match: "Exercise 7.2" }
+        localCommand:
+          js: "cd js && node --test \"test/m07-*.test.js\""
+          scala: "cd scala && ./test.sh M07"
+          fsharp: "cd fsharp && ./test.sh M07"
+      - id: m07-ex-sequence
+        title: "Exercise 7.3 — `sequence`, `draw`, `randomSeed`, `drawScene`"
+        type: exercise
+        file: "course/07-the-io-type.md"
+        anchor: exercise-73--sequence-draw-randomseed-drawscene
+        hints: { file: "course/07-the-io-type.md", match: "Exercise 7.3" }
+        localCommand:
+          js: "cd js && node --test \"test/m07-*.test.js\""
+          scala: "cd scala && ./test.sh M07"
+          fsharp: "cd fsharp && ./test.sh M07"
+      - id: m07-ex-trace
+        title: "Exercise 7.4 — `trace`, the pure interpreter"
+        type: exercise
+        file: "course/07-the-io-type.md"
+        anchor: exercise-74--trace-the-pure-interpreter
+        hints: { file: "course/07-the-io-type.md", match: "Exercise 7.4" }
+        localCommand:
+          js: "cd js && node --test \"test/m07-*.test.js\""
+          scala: "cd scala && ./test.sh M07"
+          fsharp: "cd fsharp && ./test.sh M07"
+  - id: m08
+    title: "Event streams"
+    lessons:
+      - { id: m08-text, title: "Event streams", type: text, file: "course/08-event-streams.md" }
+      - id: m08-ex-run
+        title: "Exercise 8.1 — `run`"
+        type: exercise
+        file: "course/08-event-streams.md"
+        anchor: exercise-81--run
+        hints: { file: "course/08-event-streams.md", match: "Exercise 8.1" }
+        localCommand:
+          js: "cd js && node --test \"test/m08-*.test.js\""
+          scala: "cd scala && ./test.sh M08"
+          fsharp: "cd fsharp && ./test.sh M08"
+      - id: m08-ex-keydowns
+        title: "Exercise 8.2 — sources: `keyDowns`, `keyUps`, `interval`"
+        type: exercise
+        file: "course/08-event-streams.md"
+        anchor: exercise-82--sources-keydowns-keyups-interval
+        hints: { file: "course/08-event-streams.md", match: "Exercise 8.2" }
+        localCommand:
+          js: "cd js && node --test \"test/m08-*.test.js\""
+          scala: "cd scala && ./test.sh M08"
+          fsharp: "cd fsharp && ./test.sh M08"
+      - id: m08-ex-map
+        title: "Exercise 8.3 — `map`, `filter`, `filterMap`"
+        type: exercise
+        file: "course/08-event-streams.md"
+        anchor: exercise-83--map-filter-filtermap
+        hints: { file: "course/08-event-streams.md", match: "Exercise 8.3 / 8.4" }
+        localCommand:
+          js: "cd js && node --test \"test/m08-*.test.js\""
+          scala: "cd scala && ./test.sh M08"
+          fsharp: "cd fsharp && ./test.sh M08"
+      - id: m08-ex-merge
+        title: "Exercise 8.4 — `merge`, `scan`, `startWith`"
+        type: exercise
+        file: "course/08-event-streams.md"
+        anchor: exercise-84--merge-scan-startwith
+        hints: { file: "course/08-event-streams.md", match: "Exercise 8.4" }
+        localCommand:
+          js: "cd js && node --test \"test/m08-*.test.js\""
+          scala: "cd scala && ./test.sh M08"
+          fsharp: "cd fsharp && ./test.sh M08"
+  - id: m09
+    title: "Wiring it together"
+    lessons:
+      - { id: m09-text, title: "Wiring it together", type: text, file: "course/09-wiring-it-together.md" }
+      - id: m09-ex-keytoaction
+        title: "Exercise 9.1 — `keyToAction`"
+        type: exercise
+        file: "course/09-wiring-it-together.md"
+        anchor: exercise-91--keytoaction
+        hints: { file: "course/09-wiring-it-together.md", match: "Exercise 9.1" }
+        localCommand:
+          js: "cd js && node --test \"test/m09-*.test.js\""
+          scala: "cd scala && ./test.sh M09"
+          fsharp: "cd fsharp && ./test.sh M09"
+      - id: m09-ex-classicactions
+        title: "Exercise 9.2 — the app: `classicActions`, `states`, `render`, `main`"
+        type: exercise
+        file: "course/09-wiring-it-together.md"
+        anchor: exercise-92--the-app-classicactions-states-render-main
+        hints: { file: "course/09-wiring-it-together.md", match: "Exercise 9.2" }
+        localCommand:
+          js: "cd js && node --test \"test/m09-*.test.js\""
+          scala: "cd scala && ./test.sh M09"
+          fsharp: "cd fsharp && ./test.sh M09"
+      - id: m09-ex-runio
+        title: "Exercise 9.3 — the runtime: `runIO` and `runApp`"
+        type: exercise
+        file: "course/09-wiring-it-together.md"
+        anchor: exercise-93--the-runtime-runio-and-runapp
+        hints: { file: "course/09-wiring-it-together.md", match: "Exercise 9.3" }
+        localCommand:
+          js: "cd js && node --test \"test/m09-*.test.js\""
+          scala: "cd scala && ./test.sh M09"
+          fsharp: "cd fsharp && ./test.sh M09"
+      - id: m09-ex-browserplatform
+        title: "Exercise 9.4 (JS only) — `browserPlatform`"
+        type: exercise
+        file: "course/09-wiring-it-together.md"
+        anchor: exercise-94-js-only--browserplatform
+        localCommand:
+          js: "cd js && node --test \"test/m09-*.test.js\""
+          scala: "cd scala && ./test.sh M09"
+          fsharp: "cd fsharp && ./test.sh M09"
+  - id: m10
+    title: "Extensions, all pure"
+    lessons:
+      - { id: m10-text, title: "Extensions, all pure", type: text, file: "course/10-extensions.md" }
+      - id: m10-ex-movesevery
+        title: "Exercise 10.1 — `movesEvery`"
+        type: exercise
+        file: "course/10-extensions.md"
+        anchor: exercise-101--movesevery
+        localCommand:
+          js: "cd js && node --test \"test/m10-*.test.js\""
+          scala: "cd scala && ./test.sh M10"
+          fsharp: "cd fsharp && ./test.sh M10"
+      - id: m10-ex-update
+        title: "Exercise 10.2 — `update`: `TogglePause`, `Restart`, `Frame`"
+        type: exercise
+        file: "course/10-extensions.md"
+        anchor: exercise-102--update-togglepause-restart-frame
+        hints: { file: "course/10-extensions.md", match: "Exercise 10.2" }
+        localCommand:
+          js: "cd js && node --test \"test/m10-*.test.js\""
+          scala: "cd scala && ./test.sh M10"
+          fsharp: "cd fsharp && ./test.sh M10"
+      - id: m10-ex-two-more-keys
+        title: "Exercise 10.3 — two more keys"
+        type: exercise
+        file: "course/10-extensions.md"
+        anchor: exercise-103--two-more-keys
+        localCommand:
+          js: "cd js && node --test \"test/m10-*.test.js\""
+          scala: "cd scala && ./test.sh M10"
+          fsharp: "cd fsharp && ./test.sh M10"
+      - id: m10-ex-the-frame-clock
+        title: "Exercise 10.4 — the frame clock"
+        type: exercise
+        file: "course/10-extensions.md"
+        anchor: exercise-104--the-frame-clock
+        hints: { file: "course/10-extensions.md", match: "Exercise 10.4" }
+        localCommand:
+          js: "cd js && node --test \"test/m10-*.test.js\""
+          scala: "cd scala && ./test.sh M10"
+          fsharp: "cd fsharp && ./test.sh M10"
+  - id: m11
+    title: "Capstone: Pong, by the method"
+    lessons:
+      - { id: m11-text, title: "Capstone: Pong, by the method", type: text, file: "course/11-capstone-pong.md" }
+      - id: m11-ex-model
+        title: "Exercise 11.1 — model"
+        type: exercise
+        file: "course/11-capstone-pong.md"
+        anchor: exercise-111--model
+        localCommand:
+          js: "cd js && node --test \"test/m11-*.test.js\""
+          scala: "cd scala && ./test.sh M11"
+          fsharp: "cd fsharp && ./test.sh M11"
+      - id: m11-ex-rules
+        title: "Exercise 11.2 — rules"
+        type: exercise
+        file: "course/11-capstone-pong.md"
+        anchor: exercise-112--rules
+        hints: { file: "course/11-capstone-pong.md", match: "Exercise 11.2" }
+        localCommand:
+          js: "cd js && node --test \"test/m11-*.test.js\""
+          scala: "cd scala && ./test.sh M11"
+          fsharp: "cd fsharp && ./test.sh M11"
+      - id: m11-ex-view
+        title: "Exercise 11.3 — view"
+        type: exercise
+        file: "course/11-capstone-pong.md"
+        anchor: exercise-113--view
+        localCommand:
+          js: "cd js && node --test \"test/m11-*.test.js\""
+          scala: "cd scala && ./test.sh M11"
+          fsharp: "cd fsharp && ./test.sh M11"
+      - id: m11-ex-keys-and-wiring
+        title: "Exercise 11.4 — keys and wiring"
+        type: exercise
+        file: "course/11-capstone-pong.md"
+        anchor: exercise-114--keys-and-wiring
+        hints: { file: "course/11-capstone-pong.md", match: "Exercise 11.4" }
+        localCommand:
+          js: "cd js && node --test \"test/m11-*.test.js\""
+          scala: "cd scala && ./test.sh M11"
+          fsharp: "cd fsharp && ./test.sh M11"
+  - id: ref
+    title: "Method and reference"
+    lessons:
+      - { id: ref-method, title: "The method", type: text, file: course/method.md }
+      - { id: ref-reference, title: "Reference", type: text, file: course/reference.md }
diff --git a/overlays/systemic-design/stcourse.yaml b/overlays/systemic-design/stcourse.yaml
new file mode 100644
index 0000000..8b88222
--- /dev/null
+++ b/overlays/systemic-design/stcourse.yaml
@@ -0,0 +1,110 @@
+schema: 1
+id: systemic-design
+title: Systemic Design
+pitch: Learn to build a rule-driven game engine by writing the systems that make its rules compose.
+visibility: public
+gating: sequential
+root: /home/user/systemic-design-course
+tracks:
+  - { id: rust, label: Rust }
+  - { id: ts, label: TypeScript }
+mentor: mentor/SKILL.md
+source: { kind: authored }
+modules:
+  - id: m00
+    title: "The Rewrite Trap"
+    lessons:
+      - id: m00-lesson
+        title: "The Rewrite Trap"
+        type: text
+        file: "course/00-rewrite-trap/lesson.md"
+  - id: m01
+    title: "Handles and order of play"
+    lessons:
+      - id: m01-lesson
+        title: "Handles and order of play"
+        type: text
+        file: "course/01-handles/lesson.md"
+        localCommand: "node tools/start-module.mjs 01 <your-workspace>"
+      - { id: m01-scenarios, title: Scenarios, type: text, file: "course/01-handles/scenarios.md" }
+  - id: m02
+    title: "The action queue, depth-first"
+    lessons:
+      - id: m02-lesson
+        title: "The action queue, depth-first"
+        type: text
+        file: "course/02-action-queue/lesson.md"
+        localCommand: "node tools/start-module.mjs 02 <your-workspace>"
+      - { id: m02-scenarios, title: Scenarios, type: text, file: "course/02-action-queue/scenarios.md" }
+  - id: m03
+    title: "Deferred death"
+    lessons:
+      - id: m03-lesson
+        title: "Deferred death"
+        type: text
+        file: "course/03-death-step/lesson.md"
+        localCommand: "node tools/start-module.mjs 03 <your-workspace>"
+      - { id: m03-scenarios, title: Scenarios, type: text, file: "course/03-death-step/scenarios.md" }
+  - id: m04
+    title: "Interceptors and \"trigger twice\""
+    lessons:
+      - id: m04-lesson
+        title: "Interceptors and \"trigger twice\""
+        type: text
+        file: "course/04-interceptors/lesson.md"
+        localCommand: "node tools/start-module.mjs 04 <your-workspace>"
+      - { id: m04-scenarios, title: Scenarios, type: text, file: "course/04-interceptors/scenarios.md" }
+  - id: m05
+    title: "Behavior as data and Assemble"
+    lessons:
+      - id: m05-lesson
+        title: "Behavior as data and Assemble"
+        type: text
+        file: "course/05-assemble/lesson.md"
+        localCommand: "node tools/start-module.mjs 05 <your-workspace>"
+      - { id: m05-scenarios, title: Scenarios, type: text, file: "course/05-assemble/scenarios.md" }
+  - id: m06
+    title: "Grid, lexer and parser"
+    lessons:
+      - id: m06-lesson
+        title: "Grid, lexer and parser"
+        type: text
+        file: "course/06-parser/lesson.md"
+        localCommand: "node tools/start-module.mjs 06 <your-workspace>"
+      - { id: m06-scenarios, title: Scenarios, type: text, file: "course/06-parser/scenarios.md" }
+  - id: m07
+    title: "Resolving rules: NOT, identity, meta-nouns"
+    lessons:
+      - id: m07-lesson
+        title: "Resolving rules: NOT, identity, meta-nouns"
+        type: text
+        file: "course/07-rule-resolution/lesson.md"
+        localCommand: "node tools/start-module.mjs 07 <your-workspace>"
+      - { id: m07-scenarios, title: Scenarios, type: text, file: "course/07-rule-resolution/scenarios.md" }
+  - id: m08
+    title: "Push chains: validate, then commit"
+    lessons:
+      - id: m08-lesson
+        title: "Push chains: validate, then commit"
+        type: text
+        file: "course/08-push-chains/lesson.md"
+        localCommand: "node tools/start-module.mjs 08 <your-workspace>"
+      - { id: m08-scenarios, title: Scenarios, type: text, file: "course/08-push-chains/scenarios.md" }
+  - id: m09
+    title: "The turn pipeline"
+    lessons:
+      - id: m09-lesson
+        title: "The turn pipeline"
+        type: text
+        file: "course/09-turn-pipeline/lesson.md"
+        localCommand: "node tools/start-module.mjs 09 <your-workspace>"
+      - { id: m09-scenarios, title: Scenarios, type: text, file: "course/09-turn-pipeline/scenarios.md" }
+  - id: m10
+    title: "SpellGrid"
+    lessons:
+      - id: m10-lesson
+        title: "SpellGrid"
+        type: text
+        file: "course/10-spellgrid/lesson.md"
+        localCommand: "node tools/start-module.mjs 10 <your-workspace>"
+      - { id: m10-scenarios, title: Scenarios, type: text, file: "course/10-spellgrid/scenarios.md" }
diff --git a/packages/course-format/test/reference.test.ts b/packages/course-format/test/reference.test.ts
new file mode 100644
index 0000000..61d9f33
--- /dev/null
+++ b/packages/course-format/test/reference.test.ts
@@ -0,0 +1,32 @@
+import { describe, expect, test } from "bun:test";
+import { existsSync } from "node:fs";
+import { resolve } from "node:path";
+import { createCourseRepository, extractHints } from "../src/index";
+
+const overlays = resolve(import.meta.dir, "../../../overlays");
+const snakeRoot = "/home/user/functional-programming-course";
+const systemicRoot = "/home/user/systemic-design-course";
+
+describe("reference courses", () => {
+  test.skipIf(!existsSync(snakeRoot))("pure-snake loads cleanly", async () => {
+    const repo = await createCourseRepository([overlays]);
+    const c = repo.get("pure-snake")!;
+    expect(c.diagnostics.filter((d) => d.level === "error")).toEqual([]);
+    expect(c.status).toBe("ok");
+    expect(c.manifest!.modules).toHaveLength(13);
+    expect(c.lessonIndex.has("m03-ex-move")).toBe(true);
+    const hints = c.lessonIndex.get("m03-ex-move")!.lesson.hints!;
+    const md = await Bun.file(repo.resolvePath("pure-snake", hints.file)!).text();
+    expect(extractHints(md, hints.match)).toHaveLength(3);
+    expect(await repo.readLessonMarkdown("pure-snake", "m03-ex-move")).toStartWith("### Exercise 3.1");
+  });
+
+  test.skipIf(!existsSync(systemicRoot))("systemic-design loads cleanly", async () => {
+    const repo = await createCourseRepository([overlays]);
+    const c = repo.get("systemic-design")!;
+    expect(c.diagnostics.filter((d) => d.level === "error")).toEqual([]);
+    expect(c.status).toBe("ok");
+    expect(c.manifest!.modules).toHaveLength(11);
+    expect(c.manifest!.gating).toBe("sequential");
+  });
+});

From a82ab18bee76eb381135ba4879e8733646cd3390 Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 02:54:23 +0100
Subject: [PATCH 07/14] fix(course-format): directories are not lesson files; a
 failing course never rejects loadAll

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 packages/course-format/src/load.ts       | 37 ++++++++++++++++++++----
 packages/course-format/test/load.test.ts | 28 ++++++++++++++++++
 2 files changed, 59 insertions(+), 6 deletions(-)

diff --git a/packages/course-format/src/load.ts b/packages/course-format/src/load.ts
index b0e3c57..32065f6 100644
--- a/packages/course-format/src/load.ts
+++ b/packages/course-format/src/load.ts
@@ -1,5 +1,5 @@
 import { readdir, readFile, realpath } from "node:fs/promises";
-import { realpathSync } from "node:fs";
+import { realpathSync, statSync } from "node:fs";
 import { basename, dirname, isAbsolute, join, relative, resolve, sep } from "node:path";
 import { extractHints, extractSection } from "./markdown";
 import { parseManifest, type Lesson, type Manifest } from "./schema";
@@ -67,8 +67,27 @@ export async function discoverManifests(courseDirs: string[]): Promise<string[]>
   return found;
 }
 
+/** Never throws: an unexpected failure becomes an error diagnostic on that course only. */
 export async function loadCourse(manifestPath: string): Promise<LoadedCourse> {
   manifestPath = resolve(manifestPath);
+  const dir = dirname(manifestPath);
+  try {
+    return await loadCourseUnsafe(manifestPath);
+  } catch (e) {
+    const id = basename(dir);
+    return {
+      id,
+      manifestPath,
+      root: dir,
+      manifest: null,
+      status: "error",
+      diagnostics: [{ level: "error", courseId: id, path: manifestPath, message: `unexpected error loading course: ${(e as Error).message}` }],
+      lessonIndex: new Map(),
+    };
+  }
+}
+
+async function loadCourseUnsafe(manifestPath: string): Promise<LoadedCourse> {
   const dir = dirname(manifestPath);
   const diagnostics: Diagnostic[] = [];
   const course: LoadedCourse = {
@@ -118,10 +137,16 @@ export async function loadCourse(manifestPath: string): Promise<LoadedCourse> {
     if (!mdCache.has(abs)) mdCache.set(abs, await Bun.file(abs).text());
     return mdCache.get(abs)!;
   };
-  /** Reports an error and returns false when `rel` does not exist inside the root. */
-  const requireFile = (rel: string, what: string, lessonId?: string): boolean => {
-    if (resolveInside(root, rel)) return true;
-    err(`${what} not found: ${rel}`, { lessonId, path: rel });
+  /** Reports an error and returns false when `rel` is not a regular file (or directory, if asked) inside the root. */
+  const requireFile = (rel: string, what: string, lessonId?: string, dir = false): boolean => {
+    const abs = resolveInside(root, rel);
+    if (!abs) {
+      err(`${what} not found: ${rel}`, { lessonId, path: rel });
+      return false;
+    }
+    const st = statSync(abs);
+    if (dir ? st.isDirectory() : st.isFile()) return true;
+    err(`${what} is not a ${dir ? "directory" : "regular file"}: ${rel}`, { lessonId, path: rel });
     return false;
   };
 
@@ -131,7 +156,7 @@ export async function loadCourse(manifestPath: string): Promise<LoadedCourse> {
   for (const a of manifest.attachments ?? []) requireFile(a.file, "attachment");
 
   for (const mod of manifest.modules) {
-    if (mod.code) requireFile(mod.code.dir, `module "${mod.id}" code dir`);
+    if (mod.code) requireFile(mod.code.dir, `module "${mod.id}" code dir`, undefined, true);
     for (const l of mod.lessons) {
       const id = l.id;
       let fileOk = true;
diff --git a/packages/course-format/test/load.test.ts b/packages/course-format/test/load.test.ts
index a93f3d3..ad14892 100644
--- a/packages/course-format/test/load.test.ts
+++ b/packages/course-format/test/load.test.ts
@@ -80,6 +80,34 @@ describe("overlays and errors", () => {
     expect(errs[2]!.message).toContain("Exercise 1");
   });
 
+  test("lesson file that is a directory gives a diagnostic", async () => {
+    const d = await tmp();
+    await Bun.write(join(d, "adir/x.md"), "# X\n");
+    await Bun.write(join(d, "stcourse.yaml"), manifest("dirs", "", "      - { id: as-file, title: L, type: text, file: adir }"));
+    const c = await loadCourse(join(d, "stcourse.yaml"));
+    expect(c.status).toBe("error");
+    const e = c.diagnostics.filter((x) => x.level === "error");
+    expect(e).toHaveLength(1);
+    expect(e[0]!.lessonId).toBe("as-file");
+    expect(e[0]!.path).toBe("adir");
+  });
+
+  test("one throwing course does not break loadAll", async () => {
+    const d = await tmp();
+    await Bun.write(join(d, "bad/adir/x.md"), "# X\n");
+    await Bun.write(join(d, "bad/a.md"), "# A\n## Sec\n");
+    await Bun.write(
+      join(d, "bad/stcourse.yaml"),
+      manifest("bad", "", "      - { id: h, title: L, type: exercise, file: a.md, hints: { file: adir, match: 'E' } }"),
+    );
+    await Bun.write(join(d, "good/a.md"), "# A\n");
+    await Bun.write(join(d, "good/stcourse.yaml"), manifest("good", "", "      - { id: l, title: L, type: text, file: a.md }"));
+    const all = await loadAll([d]);
+    expect(all.map((c) => c.id).sort()).toEqual(["bad", "good"]);
+    expect(all.find((c) => c.id === "bad")!.status).toBe("error");
+    expect(all.find((c) => c.id === "good")!.status).toBe("ok");
+  });
+
   test("invalid manifest gives an error course and does not throw", async () => {
     const d = await tmp();
     await Bun.write(join(d, "stcourse.yaml"), "schema: 2\nid: x\n");

From f71a31a5f157d13403138793997e8c9a277040b2 Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 02:55:38 +0100
Subject: [PATCH 08/14] fix(course-format): validate anchor file via
 requireFile; real throw test for loadCourse catch

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 packages/course-format/src/load.ts       | 11 ++++++-
 packages/course-format/test/load.test.ts | 40 +++++++++++++++++-------
 2 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/packages/course-format/src/load.ts b/packages/course-format/src/load.ts
index 32065f6..579d6ee 100644
--- a/packages/course-format/src/load.ts
+++ b/packages/course-format/src/load.ts
@@ -138,7 +138,16 @@ async function loadCourseUnsafe(manifestPath: string): Promise<LoadedCourse> {
     return mdCache.get(abs)!;
   };
   /** Reports an error and returns false when `rel` is not a regular file (or directory, if asked) inside the root. */
+  const checked = new Map<string, boolean>(); // one diagnostic per (lesson, path)
   const requireFile = (rel: string, what: string, lessonId?: string, dir = false): boolean => {
+    const key = `${lessonId ?? ""}\0${rel}\0${dir}`;
+    const prior = checked.get(key);
+    if (prior !== undefined) return prior;
+    const ok = checkFile(rel, what, lessonId, dir);
+    checked.set(key, ok);
+    return ok;
+  };
+  const checkFile = (rel: string, what: string, lessonId: string | undefined, dir: boolean): boolean => {
     const abs = resolveInside(root, rel);
     if (!abs) {
       err(`${what} not found: ${rel}`, { lessonId, path: rel });
@@ -174,7 +183,7 @@ async function loadCourseUnsafe(manifestPath: string): Promise<LoadedCourse> {
         const file = l.file ?? l.hints?.file;
         if (!file) {
           err(`anchor "${l.anchor}" given but the lesson has no file`, { lessonId: id });
-        } else if (fileOk) {
+        } else if (fileOk && requireFile(file, l.file ? "lesson file" : "hints file", id)) {
           const md = await readMd(file);
           if (md !== null && extractSection(md, l.anchor) === null) {
             err(`anchor "${l.anchor}" not found in ${file}`, { lessonId: id, path: file });
diff --git a/packages/course-format/test/load.test.ts b/packages/course-format/test/load.test.ts
index ad14892..2a8c0d6 100644
--- a/packages/course-format/test/load.test.ts
+++ b/packages/course-format/test/load.test.ts
@@ -1,5 +1,5 @@
 import { afterAll, describe, expect, test } from "bun:test";
-import { mkdtemp, rm, symlink } from "node:fs/promises";
+import { chmod, mkdtemp, rm, symlink } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join, resolve } from "node:path";
 import { createCourseRepository, discoverManifests, loadAll, loadCourse } from "../src/index";
@@ -92,20 +92,38 @@ describe("overlays and errors", () => {
     expect(e[0]!.path).toBe("adir");
   });
 
-  test("one throwing course does not break loadAll", async () => {
+  test("anchor resolved through a hints.file directory (no lesson file) gives one lesson diagnostic and loading continues", async () => {
+    const d = await tmp();
+    await Bun.write(join(d, "adir/x.md"), "# X\n");
+    const lessons = [
+      "      - { id: via-hints, title: L, type: exercise, anchor: sec, hints: { file: adir, match: 'E' } }",
+      "      - { id: after, title: L, type: text, file: missing.md }",
+    ].join("\n");
+    await Bun.write(join(d, "stcourse.yaml"), manifest("dirs2", "", lessons));
+    const c = await loadCourse(join(d, "stcourse.yaml"));
+    const e = c.diagnostics.filter((x) => x.level === "error");
+    expect(e.map((x) => x.lessonId)).toEqual(["via-hints", "after"]);
+    expect(e[0]!.path).toBe("adir");
+  });
+
+  // An unreadable file passes requireFile (it is a regular file) but Bun.file().text() rejects.
+  test.skipIf(process.getuid?.() === 0)("one throwing course does not break loadAll", async () => {
     const d = await tmp();
-    await Bun.write(join(d, "bad/adir/x.md"), "# X\n");
     await Bun.write(join(d, "bad/a.md"), "# A\n## Sec\n");
-    await Bun.write(
-      join(d, "bad/stcourse.yaml"),
-      manifest("bad", "", "      - { id: h, title: L, type: exercise, file: a.md, hints: { file: adir, match: 'E' } }"),
-    );
+    await chmod(join(d, "bad/a.md"), 0o000);
+    await Bun.write(join(d, "bad/stcourse.yaml"), manifest("bad", "", "      - { id: l, title: L, type: text, file: a.md, anchor: sec }"));
     await Bun.write(join(d, "good/a.md"), "# A\n");
     await Bun.write(join(d, "good/stcourse.yaml"), manifest("good", "", "      - { id: l, title: L, type: text, file: a.md }"));
-    const all = await loadAll([d]);
-    expect(all.map((c) => c.id).sort()).toEqual(["bad", "good"]);
-    expect(all.find((c) => c.id === "bad")!.status).toBe("error");
-    expect(all.find((c) => c.id === "good")!.status).toBe("ok");
+    try {
+      const all = await loadAll([d]);
+      expect(all.map((c) => c.id).sort()).toEqual(["bad", "good"]);
+      const bad = all.find((c) => c.id === "bad")!;
+      expect(bad.status).toBe("error");
+      expect(bad.diagnostics[0]!.message).toContain("unexpected error");
+      expect(all.find((c) => c.id === "good")!.status).toBe("ok");
+    } finally {
+      await chmod(join(d, "bad/a.md"), 0o644);
+    }
   });
 
   test("invalid manifest gives an error course and does not throw", async () => {

From 738d813fb8ccea4973e65f6eb5c85af86a0ac48f Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 02:57:34 +0100
Subject: [PATCH 09/14] feat(db): Bun.SQL connection and portable migrations

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 packages/contracts/src/server.ts     |  3 +-
 packages/db/migrations/0001_init.sql | 68 ++++++++++++++++++++++++++++
 packages/db/src/connect.ts           | 21 +++++++++
 packages/db/src/index.ts             |  2 +
 packages/db/src/migrate.ts           | 27 +++++++++++
 packages/db/test/helpers.ts          | 28 ++++++++++++
 packages/db/test/migrate.test.ts     | 32 +++++++++++++
 scripts/test-pg.sh                   | 14 ++++++
 8 files changed, 193 insertions(+), 2 deletions(-)
 create mode 100644 packages/db/migrations/0001_init.sql
 create mode 100644 packages/db/src/connect.ts
 create mode 100644 packages/db/src/index.ts
 create mode 100644 packages/db/src/migrate.ts
 create mode 100644 packages/db/test/helpers.ts
 create mode 100644 packages/db/test/migrate.test.ts
 create mode 100755 scripts/test-pg.sh

diff --git a/packages/contracts/src/server.ts b/packages/contracts/src/server.ts
index 4dfd75f..1ac169e 100644
--- a/packages/contracts/src/server.ts
+++ b/packages/contracts/src/server.ts
@@ -14,8 +14,7 @@ export type JobStatus = "queued" | "running" | "done" | "failed";
 export interface JobRecord { id: string; kind: string; status: JobStatus; progress: number; message: string | null; payload: unknown; result: unknown; error: string | null; createdAt: string; updatedAt: string }
 export interface JobQueue { enqueue(kind: string, payload: unknown): Promise<string>; get(id: string): Promise<JobRecord | null>; list(kind?: string): Promise<JobRecord[]> }
 export interface AuthService { userFromRequest(req: Request): Promise<AuthUser | null> }
-// Placeholder until Task 7 (@stc/db) exists.
-type Db = unknown;
+import type { Db } from "@stc/db";
 export interface ServerContext {
   config: AppConfig; db: Db; courses: CourseRepository;
   jobs: JobQueue; auth: AuthService;
diff --git a/packages/db/migrations/0001_init.sql b/packages/db/migrations/0001_init.sql
new file mode 100644
index 0000000..ade4751
--- /dev/null
+++ b/packages/db/migrations/0001_init.sql
@@ -0,0 +1,68 @@
+-- Portable SQL: TEXT ids and ISO-8601 timestamps, INTEGER booleans, TEXT JSON.
+CREATE TABLE user_roles (
+  user_id TEXT NOT NULL, role TEXT NOT NULL,
+  PRIMARY KEY (user_id, role)
+);
+CREATE TABLE groups (id TEXT PRIMARY KEY, name TEXT NOT NULL UNIQUE);
+CREATE TABLE group_members (
+  group_id TEXT NOT NULL, user_id TEXT NOT NULL,
+  PRIMARY KEY (group_id, user_id)
+);
+CREATE TABLE course_authors (
+  course_id TEXT NOT NULL, user_id TEXT NOT NULL,
+  PRIMARY KEY (course_id, user_id)
+);
+CREATE TABLE course_acl (
+  course_id TEXT NOT NULL,
+  principal_type TEXT NOT NULL CHECK (principal_type IN ('user', 'group')),
+  principal_id TEXT NOT NULL,
+  PRIMARY KEY (course_id, principal_type, principal_id)
+);
+CREATE TABLE progress (
+  user_id TEXT NOT NULL, course_id TEXT NOT NULL, lesson_id TEXT NOT NULL,
+  state TEXT NOT NULL CHECK (state IN ('not-started', 'in-progress', 'done')),
+  position_seconds REAL,
+  updated_at TEXT NOT NULL,
+  PRIMARY KEY (user_id, course_id, lesson_id)
+);
+CREATE TABLE notes (
+  id TEXT PRIMARY KEY, user_id TEXT NOT NULL, course_id TEXT NOT NULL, lesson_id TEXT NOT NULL,
+  anchor_kind TEXT NOT NULL CHECK (anchor_kind IN ('none', 'video', 'slide')),
+  anchor_value TEXT, deck_id TEXT,
+  body TEXT NOT NULL, created_at TEXT NOT NULL, updated_at TEXT NOT NULL
+);
+CREATE INDEX notes_by_lesson ON notes (user_id, course_id, lesson_id);
+CREATE TABLE exercise_attempts (
+  user_id TEXT NOT NULL, course_id TEXT NOT NULL, lesson_id TEXT NOT NULL, track TEXT NOT NULL,
+  code TEXT NOT NULL, result_json TEXT, passed INTEGER NOT NULL, updated_at TEXT NOT NULL,
+  PRIMARY KEY (user_id, course_id, lesson_id, track)
+);
+CREATE TABLE user_api_keys (
+  user_id TEXT NOT NULL, provider TEXT NOT NULL, ciphertext TEXT NOT NULL, created_at TEXT NOT NULL,
+  PRIMARY KEY (user_id, provider)
+);
+CREATE TABLE ai_settings (
+  scope TEXT NOT NULL CHECK (scope IN ('server', 'user')),
+  owner_id TEXT NOT NULL, -- '' for server scope
+  mentor_off INTEGER NOT NULL, config_json TEXT NOT NULL, updated_at TEXT NOT NULL,
+  PRIMARY KEY (scope, owner_id)
+);
+CREATE TABLE ai_conversations (
+  id TEXT PRIMARY KEY, user_id TEXT NOT NULL, course_id TEXT NOT NULL, title TEXT, created_at TEXT NOT NULL
+);
+CREATE TABLE ai_messages (
+  id TEXT PRIMARY KEY, conversation_id TEXT NOT NULL, role TEXT NOT NULL, content TEXT NOT NULL, created_at TEXT NOT NULL
+);
+CREATE INDEX ai_messages_by_conversation ON ai_messages (conversation_id);
+CREATE TABLE library_settings (key TEXT PRIMARY KEY, value TEXT NOT NULL);
+CREATE TABLE collections (id TEXT PRIMARY KEY, title TEXT NOT NULL, sort INTEGER NOT NULL);
+CREATE TABLE collection_courses (
+  collection_id TEXT NOT NULL, course_id TEXT NOT NULL, sort INTEGER NOT NULL,
+  PRIMARY KEY (collection_id, course_id)
+);
+CREATE TABLE jobs (
+  id TEXT PRIMARY KEY, kind TEXT NOT NULL, status TEXT NOT NULL, progress REAL NOT NULL,
+  message TEXT, payload_json TEXT NOT NULL, result_json TEXT, error TEXT,
+  created_at TEXT NOT NULL, updated_at TEXT NOT NULL
+);
+CREATE INDEX jobs_by_status ON jobs (status);
diff --git a/packages/db/src/connect.ts b/packages/db/src/connect.ts
new file mode 100644
index 0000000..f30818a
--- /dev/null
+++ b/packages/db/src/connect.ts
@@ -0,0 +1,21 @@
+import { mkdirSync } from "node:fs";
+import { dirname } from "node:path";
+
+export type Db = { sql: Bun.SQL; dialect: "sqlite" | "postgres"; close(): Promise<void> };
+
+export async function connect(url: string): Promise<Db> {
+  if (url.startsWith("sqlite:")) {
+    const path = url.replace(/^sqlite:(\/\/)?/, "");
+    if (path !== ":memory:" && path !== "") mkdirSync(dirname(path), { recursive: true });
+    // A single connection keeps in-memory databases coherent and serialises writers.
+    const sql = new Bun.SQL(url, { max: 1 });
+    await sql.unsafe("PRAGMA foreign_keys = ON");
+    if (path !== ":memory:") await sql.unsafe("PRAGMA journal_mode = WAL");
+    return { sql, dialect: "sqlite", close: () => sql.close() };
+  }
+  if (url.startsWith("postgres:") || url.startsWith("postgresql:")) {
+    const sql = new Bun.SQL(url);
+    return { sql, dialect: "postgres", close: () => sql.close() };
+  }
+  throw new Error(`Unsupported database URL (expected sqlite:// or postgres://): ${url}`);
+}
diff --git a/packages/db/src/index.ts b/packages/db/src/index.ts
new file mode 100644
index 0000000..3aaa0f0
--- /dev/null
+++ b/packages/db/src/index.ts
@@ -0,0 +1,2 @@
+export { connect, type Db } from "./connect";
+export { migrate } from "./migrate";
diff --git a/packages/db/src/migrate.ts b/packages/db/src/migrate.ts
new file mode 100644
index 0000000..be5f38f
--- /dev/null
+++ b/packages/db/src/migrate.ts
@@ -0,0 +1,27 @@
+import { readdirSync, readFileSync } from "node:fs";
+import { join } from "node:path";
+import type { Db } from "./connect";
+
+const MIGRATIONS_DIR = join(import.meta.dir, "..", "migrations");
+
+function statements(text: string): string[] {
+  const noComments = text.split("\n").filter((l) => !l.trim().startsWith("--")).join("\n");
+  return noComments.split(";").map((s) => s.trim()).filter(Boolean);
+}
+
+export async function migrate(db: Db): Promise<string[]> {
+  await db.sql.unsafe("CREATE TABLE IF NOT EXISTS schema_migrations (name TEXT PRIMARY KEY, applied_at TEXT NOT NULL)");
+  const done = new Set((await db.sql`SELECT name FROM schema_migrations`).map((r: { name: string }) => r.name));
+  const files = readdirSync(MIGRATIONS_DIR).filter((f) => f.endsWith(".sql")).sort();
+  const applied: string[] = [];
+  for (const name of files) {
+    if (done.has(name)) continue;
+    const stmts = statements(readFileSync(join(MIGRATIONS_DIR, name), "utf8"));
+    await db.sql.begin(async (tx) => {
+      for (const s of stmts) await tx.unsafe(s);
+      await tx`INSERT INTO schema_migrations (name, applied_at) VALUES (${name}, ${new Date().toISOString()})`;
+    });
+    applied.push(name);
+  }
+  return applied;
+}
diff --git a/packages/db/test/helpers.ts b/packages/db/test/helpers.ts
new file mode 100644
index 0000000..b162836
--- /dev/null
+++ b/packages/db/test/helpers.ts
@@ -0,0 +1,28 @@
+import { test } from "bun:test";
+import { connect, type Db } from "../src/connect";
+import { migrate } from "../src/migrate";
+
+const PG = process.env.STC_TEST_PG_URL;
+
+/** Runs `fn` against a fresh migrated in-memory SQLite, and a fresh Postgres schema when STC_TEST_PG_URL is set. */
+export function forEachDb(name: string, fn: (db: Db) => Promise<void>): void {
+  test(`${name} [sqlite]`, async () => {
+    const db = await connect("sqlite://:memory:");
+    try { await migrate(db); await fn(db); } finally { await db.close(); }
+  });
+  if (!PG) return;
+  test(`${name} [postgres]`, async () => {
+    const schema = `t_${Bun.randomUUIDv7().replaceAll("-", "")}`;
+    const admin = await connect(PG);
+    await admin.sql.unsafe(`CREATE SCHEMA ${schema}`);
+    const u = new URL(PG);
+    u.searchParams.set("options", `-c search_path=${schema}`);
+    const db = await connect(u.toString());
+    try { await migrate(db); await fn(db); }
+    finally {
+      await db.close();
+      await admin.sql.unsafe(`DROP SCHEMA ${schema} CASCADE`);
+      await admin.close();
+    }
+  });
+}
diff --git a/packages/db/test/migrate.test.ts b/packages/db/test/migrate.test.ts
new file mode 100644
index 0000000..8619728
--- /dev/null
+++ b/packages/db/test/migrate.test.ts
@@ -0,0 +1,32 @@
+import { expect } from "bun:test";
+import { forEachDb } from "./helpers";
+import { migrate } from "../src/migrate";
+
+forEachDb("applies 0001 once", async (db) => {
+  // helpers already migrated once; a second run applies nothing
+  expect(await migrate(db)).toEqual([]);
+  const rows = await db.sql`SELECT name FROM schema_migrations`;
+  expect(rows.map((r: { name: string }) => r.name)).toEqual(["0001_init.sql"]);
+});
+
+forEachDb("all tables exist", async (db) => {
+  const s = db.sql;
+  const t = "2026-01-01T00:00:00.000Z";
+  const one = async (table: string, rows: Promise<unknown>) => { await rows; expect((await s.unsafe(`SELECT COUNT(*) AS n FROM ${table}`))[0].n.toString()).toBe("1"); };
+  await one("user_roles", s`INSERT INTO user_roles VALUES ('u','owner')`);
+  await one("groups", s`INSERT INTO groups VALUES ('g','G')`);
+  await one("group_members", s`INSERT INTO group_members VALUES ('g','u')`);
+  await one("course_authors", s`INSERT INTO course_authors VALUES ('c','u')`);
+  await one("course_acl", s`INSERT INTO course_acl VALUES ('c','user','u')`);
+  await one("progress", s`INSERT INTO progress VALUES ('u','c','l','done',1.5,${t})`);
+  await one("notes", s`INSERT INTO notes VALUES ('n','u','c','l','none',NULL,NULL,'b',${t},${t})`);
+  await one("exercise_attempts", s`INSERT INTO exercise_attempts VALUES ('u','c','l','py','x',NULL,1,${t})`);
+  await one("user_api_keys", s`INSERT INTO user_api_keys VALUES ('u','p','ct',${t})`);
+  await one("ai_settings", s`INSERT INTO ai_settings VALUES ('server','',0,'{}',${t})`);
+  await one("ai_conversations", s`INSERT INTO ai_conversations VALUES ('a','u','c',NULL,${t})`);
+  await one("ai_messages", s`INSERT INTO ai_messages VALUES ('m','a','user','hi',${t})`);
+  await one("library_settings", s`INSERT INTO library_settings VALUES ('k','v')`);
+  await one("collections", s`INSERT INTO collections VALUES ('co','T',0)`);
+  await one("collection_courses", s`INSERT INTO collection_courses VALUES ('co','c',0)`);
+  await one("jobs", s`INSERT INTO jobs VALUES ('j','k','queued',0,NULL,'{}',NULL,NULL,${t},${t})`);
+});
diff --git a/scripts/test-pg.sh b/scripts/test-pg.sh
new file mode 100755
index 0000000..45ba055
--- /dev/null
+++ b/scripts/test-pg.sh
@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+# Runs the package tests against SQLite and a throwaway postgres:17 container.
+set -euo pipefail
+PORT="${STC_PG_PORT:-55432}"
+cd "$(dirname "$0")/.."
+trap 'docker stop stc-pg >/dev/null 2>&1 || true' EXIT
+docker rm -f stc-pg >/dev/null 2>&1 || true
+docker run -d --rm --name stc-pg -e POSTGRES_PASSWORD=stc -p 127.0.0.1:${PORT}:5432 postgres:17 >/dev/null
+for _ in $(seq 1 60); do
+  docker exec stc-pg pg_isready -U postgres -h 127.0.0.1 >/dev/null 2>&1 && break
+  sleep 1
+done
+sleep 1
+STC_TEST_PG_URL="postgres://postgres:stc@127.0.0.1:${PORT}/postgres" bun test packages

From 4636273d5572327aef3a5fc52327f2ddd19842f5 Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 02:59:09 +0100
Subject: [PATCH 10/14] feat(db): progress, notes, attempts, library, jobs
 repositories

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 packages/db/src/index.ts          |   5 ++
 packages/db/src/repos/attempts.ts |  36 +++++++++
 packages/db/src/repos/jobs.ts     |  63 +++++++++++++++
 packages/db/src/repos/library.ts  |  49 ++++++++++++
 packages/db/src/repos/notes.ts    |  66 ++++++++++++++++
 packages/db/src/repos/progress.ts |  34 ++++++++
 packages/db/test/repos.test.ts    | 125 ++++++++++++++++++++++++++++++
 7 files changed, 378 insertions(+)
 create mode 100644 packages/db/src/repos/attempts.ts
 create mode 100644 packages/db/src/repos/jobs.ts
 create mode 100644 packages/db/src/repos/library.ts
 create mode 100644 packages/db/src/repos/notes.ts
 create mode 100644 packages/db/src/repos/progress.ts
 create mode 100644 packages/db/test/repos.test.ts

diff --git a/packages/db/src/index.ts b/packages/db/src/index.ts
index 3aaa0f0..7dba514 100644
--- a/packages/db/src/index.ts
+++ b/packages/db/src/index.ts
@@ -1,2 +1,7 @@
 export { connect, type Db } from "./connect";
 export { migrate } from "./migrate";
+export { progressRepo, type LessonProgress, type ProgressState } from "./repos/progress";
+export { notesRepo, type Note, type NoteInput } from "./repos/notes";
+export { attemptsRepo, type Attempt } from "./repos/attempts";
+export { libraryRepo, type Collection } from "./repos/library";
+export { jobsRepo, type JobPatch } from "./repos/jobs";
diff --git a/packages/db/src/repos/attempts.ts b/packages/db/src/repos/attempts.ts
new file mode 100644
index 0000000..843e1c2
--- /dev/null
+++ b/packages/db/src/repos/attempts.ts
@@ -0,0 +1,36 @@
+import type { Db } from "../connect";
+
+export type Attempt = {
+  userId: string; courseId: string; lessonId: string; track: string;
+  code: string; result: unknown; passed: boolean; updatedAt: string;
+};
+
+export function attemptsRepo(db: Db) {
+  return {
+    async get(userId: string, courseId: string, lessonId: string, track: string): Promise<Attempt | null> {
+      const rows = await db.sql`SELECT * FROM exercise_attempts WHERE user_id = ${userId} AND course_id = ${courseId} AND lesson_id = ${lessonId} AND track = ${track}`;
+      if (rows.length === 0) return null;
+      const r = rows[0];
+      return {
+        userId: r.user_id, courseId: r.course_id, lessonId: r.lesson_id, track: r.track,
+        code: r.code, result: r.result_json === null ? null : JSON.parse(r.result_json),
+        passed: Number(r.passed) === 1, updatedAt: r.updated_at,
+      };
+    },
+
+    async save(a: Attempt): Promise<void> {
+      const resultJson = a.result === null || a.result === undefined ? null : JSON.stringify(a.result);
+      const passed = a.passed ? 1 : 0;
+      await db.sql.begin(async (tx) => {
+        const existing = await tx`SELECT 1 AS x FROM exercise_attempts WHERE user_id = ${a.userId} AND course_id = ${a.courseId} AND lesson_id = ${a.lessonId} AND track = ${a.track}`;
+        if (existing.length > 0) {
+          await tx`UPDATE exercise_attempts SET code = ${a.code}, result_json = ${resultJson}, passed = ${passed}, updated_at = ${a.updatedAt}
+            WHERE user_id = ${a.userId} AND course_id = ${a.courseId} AND lesson_id = ${a.lessonId} AND track = ${a.track}`;
+        } else {
+          await tx`INSERT INTO exercise_attempts (user_id, course_id, lesson_id, track, code, result_json, passed, updated_at)
+            VALUES (${a.userId}, ${a.courseId}, ${a.lessonId}, ${a.track}, ${a.code}, ${resultJson}, ${passed}, ${a.updatedAt})`;
+        }
+      });
+    },
+  };
+}
diff --git a/packages/db/src/repos/jobs.ts b/packages/db/src/repos/jobs.ts
new file mode 100644
index 0000000..0713e72
--- /dev/null
+++ b/packages/db/src/repos/jobs.ts
@@ -0,0 +1,63 @@
+import type { JobRecord } from "@stc/contracts";
+import type { Db } from "../connect";
+
+// biome-ignore lint/suspicious/noExplicitAny: raw driver row
+const toJob = (r: any): JobRecord => ({
+  id: r.id, kind: r.kind, status: r.status, progress: Number(r.progress), message: r.message,
+  payload: JSON.parse(r.payload_json), result: r.result_json === null ? null : JSON.parse(r.result_json),
+  error: r.error, createdAt: r.created_at, updatedAt: r.updated_at,
+});
+
+export type JobPatch = Partial<Pick<JobRecord, "status" | "progress" | "message" | "result" | "error">>;
+
+export function jobsRepo(db: Db) {
+  const get = async (id: string): Promise<JobRecord | null> => {
+    const rows = await db.sql`SELECT * FROM jobs WHERE id = ${id}`;
+    return rows.length ? toJob(rows[0]) : null;
+  };
+
+  return {
+    get,
+
+    async insert(kind: string, payload: unknown): Promise<string> {
+      const id = Bun.randomUUIDv7();
+      const now = new Date().toISOString();
+      await db.sql`INSERT INTO jobs (id, kind, status, progress, message, payload_json, result_json, error, created_at, updated_at)
+        VALUES (${id}, ${kind}, 'queued', 0, NULL, ${JSON.stringify(payload ?? null)}, NULL, NULL, ${now}, ${now})`;
+      return id;
+    },
+
+    /**
+     * Picks the oldest queued job of one of `kinds` and flips it to running with a guarded
+     * `UPDATE ... WHERE id = ? AND status = 'queued'`. Of any concurrent claimers of the same
+     * row exactly one sees an affected count of 1 (Postgres re-checks the predicate after
+     * waiting on the row lock); losers pick the next candidate.
+     */
+    async claimNext(kinds: string[]): Promise<JobRecord | null> {
+      if (kinds.length === 0) return null;
+      for (;;) {
+        const next = await db.sql`SELECT id FROM jobs WHERE status = 'queued' AND kind IN ${db.sql(kinds)} ORDER BY created_at, id LIMIT 1`;
+        if (next.length === 0) return null;
+        const id: string = next[0].id;
+        const res = await db.sql`UPDATE jobs SET status = 'running', updated_at = ${new Date().toISOString()} WHERE id = ${id} AND status = 'queued'`;
+        if (Number(res.count) > 0) return get(id);
+      }
+    },
+
+    async update(id: string, patch: JobPatch): Promise<void> {
+      const cur = await get(id);
+      if (!cur) return;
+      const next = { ...cur, ...patch };
+      await db.sql`UPDATE jobs SET status = ${next.status}, progress = ${next.progress}, message = ${next.message ?? null},
+        result_json = ${next.result === null || next.result === undefined ? null : JSON.stringify(next.result)},
+        error = ${next.error ?? null}, updated_at = ${new Date().toISOString()} WHERE id = ${id}`;
+    },
+
+    async list(kind?: string): Promise<JobRecord[]> {
+      const rows = kind === undefined
+        ? await db.sql`SELECT * FROM jobs ORDER BY created_at, id`
+        : await db.sql`SELECT * FROM jobs WHERE kind = ${kind} ORDER BY created_at, id`;
+      return rows.map(toJob);
+    },
+  };
+}
diff --git a/packages/db/src/repos/library.ts b/packages/db/src/repos/library.ts
new file mode 100644
index 0000000..30134b1
--- /dev/null
+++ b/packages/db/src/repos/library.ts
@@ -0,0 +1,49 @@
+import type { Db } from "../connect";
+
+export type Collection = { id: string; title: string; sort: number; courseIds: string[] };
+const FEATURED = "featured_course_id";
+
+export function libraryRepo(db: Db) {
+  return {
+    async getFeatured(): Promise<string | null> {
+      const rows = await db.sql`SELECT value FROM library_settings WHERE key = ${FEATURED}`;
+      return rows.length ? rows[0].value : null;
+    },
+
+    async setFeatured(courseId: string | null): Promise<void> {
+      await db.sql.begin(async (tx) => {
+        await tx`DELETE FROM library_settings WHERE key = ${FEATURED}`;
+        if (courseId !== null) await tx`INSERT INTO library_settings (key, value) VALUES (${FEATURED}, ${courseId})`;
+      });
+    },
+
+    async listCollections(): Promise<Collection[]> {
+      const cols = await db.sql`SELECT id, title, sort FROM collections ORDER BY sort, title, id`;
+      const links = await db.sql`SELECT collection_id, course_id FROM collection_courses ORDER BY sort, course_id`;
+      return cols.map((c: { id: string; title: string; sort: number }) => ({
+        id: c.id, title: c.title, sort: Number(c.sort),
+        courseIds: links.filter((l: { collection_id: string }) => l.collection_id === c.id).map((l: { course_id: string }) => l.course_id),
+      }));
+    },
+
+    async saveCollection(c: Collection): Promise<void> {
+      await db.sql.begin(async (tx) => {
+        const existing = await tx`SELECT 1 AS x FROM collections WHERE id = ${c.id}`;
+        if (existing.length > 0) await tx`UPDATE collections SET title = ${c.title}, sort = ${c.sort} WHERE id = ${c.id}`;
+        else await tx`INSERT INTO collections (id, title, sort) VALUES (${c.id}, ${c.title}, ${c.sort})`;
+        await tx`DELETE FROM collection_courses WHERE collection_id = ${c.id}`;
+        let i = 0;
+        for (const courseId of new Set(c.courseIds)) {
+          await tx`INSERT INTO collection_courses (collection_id, course_id, sort) VALUES (${c.id}, ${courseId}, ${i++})`;
+        }
+      });
+    },
+
+    async deleteCollection(id: string): Promise<void> {
+      await db.sql.begin(async (tx) => {
+        await tx`DELETE FROM collection_courses WHERE collection_id = ${id}`;
+        await tx`DELETE FROM collections WHERE id = ${id}`;
+      });
+    },
+  };
+}
diff --git a/packages/db/src/repos/notes.ts b/packages/db/src/repos/notes.ts
new file mode 100644
index 0000000..875a2b7
--- /dev/null
+++ b/packages/db/src/repos/notes.ts
@@ -0,0 +1,66 @@
+import type { Db } from "../connect";
+
+export type Note = {
+  id: string; userId: string; courseId: string; lessonId: string;
+  anchorKind: "none" | "video" | "slide"; anchorValue: string | null; deckId: string | null;
+  body: string; createdAt: string; updatedAt: string;
+};
+export type NoteInput = {
+  userId: string; courseId: string; lessonId: string;
+  anchorKind: Note["anchorKind"]; anchorValue?: string | null; deckId?: string | null; body: string;
+};
+
+// biome-ignore lint/suspicious/noExplicitAny: raw driver row
+const toNote = (r: any): Note => ({
+  id: r.id, userId: r.user_id, courseId: r.course_id, lessonId: r.lesson_id,
+  anchorKind: r.anchor_kind, anchorValue: r.anchor_value, deckId: r.deck_id,
+  body: r.body, createdAt: r.created_at, updatedAt: r.updated_at,
+});
+
+const numeric = (v: string | null): number => {
+  const n = v === null ? NaN : Number(v);
+  return Number.isNaN(n) ? Number.POSITIVE_INFINITY : n;
+};
+
+export function notesRepo(db: Db) {
+  const getOne = async (id: string): Promise<Note | null> => {
+    const rows = await db.sql`SELECT * FROM notes WHERE id = ${id}`;
+    return rows.length ? toNote(rows[0]) : null;
+  };
+
+  return {
+    /** Ordered by anchor_kind, then anchor_value read numerically (so page 2 precedes page 10), then created_at. */
+    async list(userId: string, courseId: string, lessonId?: string): Promise<Note[]> {
+      const rows = lessonId === undefined
+        ? await db.sql`SELECT * FROM notes WHERE user_id = ${userId} AND course_id = ${courseId}`
+        : await db.sql`SELECT * FROM notes WHERE user_id = ${userId} AND course_id = ${courseId} AND lesson_id = ${lessonId}`;
+      // Numeric ordering is done here: CAST of non-numeric text errors on Postgres but not SQLite.
+      return (rows.map(toNote) as Note[]).sort((a, b) =>
+        (a.anchorKind < b.anchorKind ? -1 : a.anchorKind > b.anchorKind ? 1 : 0) ||
+        numeric(a.anchorValue) - numeric(b.anchorValue) ||
+        (a.createdAt < b.createdAt ? -1 : a.createdAt > b.createdAt ? 1 : 0) ||
+        (a.id < b.id ? -1 : 1));
+    },
+
+    async create(input: NoteInput): Promise<Note> {
+      const id = Bun.randomUUIDv7();
+      const now = new Date().toISOString();
+      await db.sql`INSERT INTO notes (id, user_id, course_id, lesson_id, anchor_kind, anchor_value, deck_id, body, created_at, updated_at)
+        VALUES (${id}, ${input.userId}, ${input.courseId}, ${input.lessonId}, ${input.anchorKind}, ${input.anchorValue ?? null}, ${input.deckId ?? null}, ${input.body}, ${now}, ${now})`;
+      return (await getOne(id))!;
+    },
+
+    async update(id: string, userId: string, body: string): Promise<Note | null> {
+      await db.sql`UPDATE notes SET body = ${body}, updated_at = ${new Date().toISOString()} WHERE id = ${id} AND user_id = ${userId}`;
+      const n = await getOne(id);
+      return n && n.userId === userId ? n : null;
+    },
+
+    async remove(id: string, userId: string): Promise<boolean> {
+      const owned = await db.sql`SELECT 1 AS x FROM notes WHERE id = ${id} AND user_id = ${userId}`;
+      if (owned.length === 0) return false;
+      await db.sql`DELETE FROM notes WHERE id = ${id} AND user_id = ${userId}`;
+      return true;
+    },
+  };
+}
diff --git a/packages/db/src/repos/progress.ts b/packages/db/src/repos/progress.ts
new file mode 100644
index 0000000..9472e30
--- /dev/null
+++ b/packages/db/src/repos/progress.ts
@@ -0,0 +1,34 @@
+import type { Db } from "../connect";
+
+export type ProgressState = "not-started" | "in-progress" | "done";
+export type LessonProgress = { state: ProgressState; positionSeconds: number | null; updatedAt: string };
+
+export function progressRepo(db: Db) {
+  return {
+    async get(userId: string, courseId: string): Promise<Record<string, LessonProgress>> {
+      const rows = await db.sql`SELECT lesson_id, state, position_seconds, updated_at FROM progress WHERE user_id = ${userId} AND course_id = ${courseId}`;
+      const out: Record<string, LessonProgress> = {};
+      for (const r of rows) {
+        out[r.lesson_id] = {
+          state: r.state,
+          positionSeconds: r.position_seconds === null ? null : Number(r.position_seconds),
+          updatedAt: r.updated_at,
+        };
+      }
+      return out;
+    },
+
+    async set(userId: string, courseId: string, lessonId: string, state: ProgressState, positionSeconds?: number): Promise<void> {
+      const now = new Date().toISOString();
+      const pos = positionSeconds ?? null;
+      await db.sql.begin(async (tx) => {
+        const existing = await tx`SELECT 1 AS x FROM progress WHERE user_id = ${userId} AND course_id = ${courseId} AND lesson_id = ${lessonId}`;
+        if (existing.length > 0) {
+          await tx`UPDATE progress SET state = ${state}, position_seconds = ${pos}, updated_at = ${now} WHERE user_id = ${userId} AND course_id = ${courseId} AND lesson_id = ${lessonId}`;
+        } else {
+          await tx`INSERT INTO progress (user_id, course_id, lesson_id, state, position_seconds, updated_at) VALUES (${userId}, ${courseId}, ${lessonId}, ${state}, ${pos}, ${now})`;
+        }
+      });
+    },
+  };
+}
diff --git a/packages/db/test/repos.test.ts b/packages/db/test/repos.test.ts
new file mode 100644
index 0000000..8169fb9
--- /dev/null
+++ b/packages/db/test/repos.test.ts
@@ -0,0 +1,125 @@
+import { expect } from "bun:test";
+import { forEachDb } from "./helpers";
+import { attemptsRepo, jobsRepo, libraryRepo, notesRepo, progressRepo } from "../src";
+
+forEachDb("progress upsert keeps one row", async (db) => {
+  const p = progressRepo(db);
+  await p.set("u", "c", "l1", "in-progress", 12.5);
+  await p.set("u", "c", "l1", "done");
+  await p.set("u", "c", "l2", "in-progress", 3);
+  await p.set("other", "c", "l1", "done");
+  const got = await p.get("u", "c");
+  expect(Object.keys(got).sort()).toEqual(["l1", "l2"]);
+  expect(got.l1.state).toBe("done");
+  expect(got.l1.positionSeconds).toBeNull();
+  expect(got.l2.positionSeconds).toBe(3);
+  expect(typeof got.l1.updatedAt).toBe("string");
+  expect((await db.sql`SELECT COUNT(*) AS n FROM progress WHERE user_id = 'u'`)[0].n.toString()).toBe("2");
+});
+
+forEachDb("notes order puts slide page 2 before page 10", async (db) => {
+  const n = notesRepo(db);
+  const base = { userId: "u", courseId: "c", lessonId: "l" };
+  await n.create({ ...base, anchorKind: "slide", anchorValue: "10", deckId: "d", body: "ten" });
+  await n.create({ ...base, anchorKind: "slide", anchorValue: "2", deckId: "d", body: "two" });
+  await n.create({ ...base, anchorKind: "none", body: "plain" });
+  await n.create({ ...base, anchorKind: "video", anchorValue: "90.5", body: "video" });
+  await n.create({ ...base, lessonId: "other", anchorKind: "none", body: "elsewhere" });
+  const all = await n.list("u", "c", "l");
+  expect(all.map((x) => x.body)).toEqual(["plain", "two", "ten", "video"]);
+  expect(all[1].deckId).toBe("d");
+  expect((await n.list("u", "c")).length).toBe(5);
+});
+
+forEachDb("another user cannot update or delete a note", async (db) => {
+  const n = notesRepo(db);
+  const note = await n.create({ userId: "u", courseId: "c", lessonId: "l", anchorKind: "none", body: "mine" });
+  expect(await n.update(note.id, "intruder", "hacked")).toBeNull();
+  expect(await n.remove(note.id, "intruder")).toBe(false);
+  expect((await n.list("u", "c", "l"))[0].body).toBe("mine");
+  expect((await n.update(note.id, "u", "edited"))?.body).toBe("edited");
+  expect(await n.remove(note.id, "u")).toBe(true);
+  expect(await n.list("u", "c", "l")).toEqual([]);
+});
+
+forEachDb("attempts round-trip", async (db) => {
+  const a = attemptsRepo(db);
+  expect(await a.get("u", "c", "l", "py")).toBeNull();
+  const att = { userId: "u", courseId: "c", lessonId: "l", track: "py", code: "print(1)", result: { out: "1", tests: [true] }, passed: true, updatedAt: "2026-01-01T00:00:00.000Z" };
+  await a.save(att);
+  expect(await a.get("u", "c", "l", "py")).toEqual(att);
+  await a.save({ ...att, code: "x", result: null, passed: false });
+  const again = await a.get("u", "c", "l", "py");
+  expect(again).toMatchObject({ code: "x", result: null, passed: false });
+});
+
+forEachDb("featured course and collections keep their order", async (db) => {
+  const l = libraryRepo(db);
+  expect(await l.getFeatured()).toBeNull();
+  await l.setFeatured("a");
+  await l.setFeatured("b");
+  expect(await l.getFeatured()).toBe("b");
+  await l.setFeatured(null);
+  expect(await l.getFeatured()).toBeNull();
+
+  await l.saveCollection({ id: "c2", title: "Second", sort: 2, courseIds: ["z", "y"] });
+  await l.saveCollection({ id: "c1", title: "First", sort: 1, courseIds: ["b", "a", "c"] });
+  expect(await l.listCollections()).toEqual([
+    { id: "c1", title: "First", sort: 1, courseIds: ["b", "a", "c"] },
+    { id: "c2", title: "Second", sort: 2, courseIds: ["z", "y"] },
+  ]);
+  await l.saveCollection({ id: "c1", title: "First!", sort: 3, courseIds: ["c", "a"] });
+  expect((await l.listCollections()).map((c) => [c.id, c.courseIds])).toEqual([["c2", ["z", "y"]], ["c1", ["c", "a"]]]);
+  await l.deleteCollection("c2");
+  expect((await l.listCollections()).map((c) => c.id)).toEqual(["c1"]);
+  expect((await db.sql`SELECT COUNT(*) AS n FROM collection_courses`)[0].n.toString()).toBe("2");
+});
+
+forEachDb("jobs lifecycle", async (db) => {
+  const j = jobsRepo(db);
+  const id = await j.insert("import", { url: "x" });
+  const got = await j.get(id);
+  expect(got).toMatchObject({ kind: "import", status: "queued", progress: 0, payload: { url: "x" }, result: null, error: null, message: null });
+  await j.update(id, { progress: 0.5, message: "half" });
+  await j.update(id, { status: "done", result: { ok: 1 } });
+  expect(await j.get(id)).toMatchObject({ status: "done", progress: 0.5, message: "half", result: { ok: 1 } });
+  await j.insert("other", {});
+  expect((await j.list()).length).toBe(2);
+  expect((await j.list("import")).map((x) => x.id)).toEqual([id]);
+  expect(await j.get("missing")).toBeNull();
+});
+
+forEachDb("claimNext returns null when nothing is queued", async (db) => {
+  const j = jobsRepo(db);
+  expect(await j.claimNext(["import"])).toBeNull();
+  await j.insert("other", {});
+  expect(await j.claimNext(["import"])).toBeNull();
+  expect(await j.claimNext([])).toBeNull();
+});
+
+forEachDb("claimNext claims oldest first and marks running", async (db) => {
+  const j = jobsRepo(db);
+  const a = await j.insert("import", 1);
+  await Bun.sleep(2);
+  const b = await j.insert("import", 2);
+  expect((await j.claimNext(["import"]))).toMatchObject({ id: a, status: "running" });
+  expect((await j.claimNext(["import"]))?.id).toBe(b);
+  expect(await j.claimNext(["import"])).toBeNull();
+});
+
+forEachDb("two concurrent claimNext calls never claim the same job", async (db) => {
+  const j = jobsRepo(db);
+  const ids = [await j.insert("k", 1), await j.insert("k", 2)];
+  for (let round = 0; round < 1; round++) {
+    const got = await Promise.all([j.claimNext(["k"]), j.claimNext(["k"])]);
+    expect(got.every((x) => x !== null)).toBe(true);
+    expect(new Set(got.map((x) => x!.id)).size).toBe(2);
+    expect([...got.map((x) => x!.id)].sort()).toEqual([...ids].sort());
+  }
+  // single job, two claimers: exactly one wins
+  const solo = jobsRepo(db);
+  await db.sql`DELETE FROM jobs`;
+  const only = await solo.insert("k", 3);
+  const res = await Promise.all([solo.claimNext(["k"]), solo.claimNext(["k"])]);
+  expect(res.filter((x) => x !== null).map((x) => x!.id)).toEqual([only]);
+});

From f061e360928c453b9a3664340bafc1e9930d2da2 Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 03:01:05 +0100
Subject: [PATCH 11/14] fix(db): jobs.update writes only patched columns; late
 progress cannot resurrect a finished job

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 packages/db/src/repos/jobs.ts  | 20 ++++++++++++++------
 packages/db/test/repos.test.ts | 25 +++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/packages/db/src/repos/jobs.ts b/packages/db/src/repos/jobs.ts
index 0713e72..3850ef6 100644
--- a/packages/db/src/repos/jobs.ts
+++ b/packages/db/src/repos/jobs.ts
@@ -44,13 +44,21 @@ export function jobsRepo(db: Db) {
       }
     },
 
+    /**
+     * Single UPDATE writing only the patched columns (plus updated_at). A progress-only patch
+     * (progress and/or message) is guarded by status = 'running', so a late report on a
+     * finished job is a no-op.
+     */
     async update(id: string, patch: JobPatch): Promise<void> {
-      const cur = await get(id);
-      if (!cur) return;
-      const next = { ...cur, ...patch };
-      await db.sql`UPDATE jobs SET status = ${next.status}, progress = ${next.progress}, message = ${next.message ?? null},
-        result_json = ${next.result === null || next.result === undefined ? null : JSON.stringify(next.result)},
-        error = ${next.error ?? null}, updated_at = ${new Date().toISOString()} WHERE id = ${id}`;
+      const set: Record<string, unknown> = { updated_at: new Date().toISOString() };
+      if (patch.status !== undefined) set.status = patch.status;
+      if (patch.progress !== undefined) set.progress = patch.progress;
+      if (patch.message !== undefined) set.message = patch.message;
+      if (patch.result !== undefined) set.result_json = patch.result === null ? null : JSON.stringify(patch.result);
+      if (patch.error !== undefined) set.error = patch.error;
+      const progressOnly = patch.status === undefined && patch.result === undefined && patch.error === undefined;
+      if (progressOnly) await db.sql`UPDATE jobs SET ${db.sql(set)} WHERE id = ${id} AND status = 'running'`;
+      else await db.sql`UPDATE jobs SET ${db.sql(set)} WHERE id = ${id}`;
     },
 
     async list(kind?: string): Promise<JobRecord[]> {
diff --git a/packages/db/test/repos.test.ts b/packages/db/test/repos.test.ts
index 8169fb9..684b455 100644
--- a/packages/db/test/repos.test.ts
+++ b/packages/db/test/repos.test.ts
@@ -80,6 +80,7 @@ forEachDb("jobs lifecycle", async (db) => {
   const id = await j.insert("import", { url: "x" });
   const got = await j.get(id);
   expect(got).toMatchObject({ kind: "import", status: "queued", progress: 0, payload: { url: "x" }, result: null, error: null, message: null });
+  await j.claimNext(["import"]);
   await j.update(id, { progress: 0.5, message: "half" });
   await j.update(id, { status: "done", result: { ok: 1 } });
   expect(await j.get(id)).toMatchObject({ status: "done", progress: 0.5, message: "half", result: { ok: 1 } });
@@ -123,3 +124,27 @@ forEachDb("two concurrent claimNext calls never claim the same job", async (db)
   const res = await Promise.all([solo.claimNext(["k"]), solo.claimNext(["k"])]);
   expect(res.filter((x) => x !== null).map((x) => x!.id)).toEqual([only]);
 });
+
+forEachDb("late progress update does not resurrect a done job", async (db) => {
+  const j = jobsRepo(db);
+  const id = await j.insert("k", {});
+  await j.claimNext(["k"]);
+  await j.update(id, { status: "done", progress: 1, result: { ok: true } });
+  await j.update(id, { progress: 0.4, message: "stale" });
+  expect(await j.get(id)).toMatchObject({ status: "done", progress: 1, message: null, result: { ok: true } });
+  const f = await j.insert("k", {});
+  await j.update(f, { status: "failed", error: "boom" });
+  await j.update(f, { progress: 0.9 });
+  expect(await j.get(f)).toMatchObject({ status: "failed", error: "boom", progress: 0 });
+});
+
+forEachDb("update only touches patched columns", async (db) => {
+  const j = jobsRepo(db);
+  const id = await j.insert("k", { a: 1 });
+  await j.claimNext(["k"]);
+  await j.update(id, { progress: 0.5, message: "working" });
+  await j.update(id, { message: "still" });
+  expect(await j.get(id)).toMatchObject({ status: "running", progress: 0.5, message: "still", result: null, error: null, payload: { a: 1 } });
+  await j.update(id, { result: { r: 1 } });
+  expect(await j.get(id)).toMatchObject({ status: "running", progress: 0.5, message: "still", result: { r: 1 } });
+});

From ea18f18b4fdf1e8dfd4e50d23ab6f29a25bcb0ff Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 03:01:31 +0100
Subject: [PATCH 12/14] fix(db): use DOUBLE PRECISION for position and progress
 columns

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 packages/db/migrations/0001_init.sql | 4 ++--
 packages/db/test/repos.test.ts       | 4 +++-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/packages/db/migrations/0001_init.sql b/packages/db/migrations/0001_init.sql
index ade4751..56ec758 100644
--- a/packages/db/migrations/0001_init.sql
+++ b/packages/db/migrations/0001_init.sql
@@ -21,7 +21,7 @@ CREATE TABLE course_acl (
 CREATE TABLE progress (
   user_id TEXT NOT NULL, course_id TEXT NOT NULL, lesson_id TEXT NOT NULL,
   state TEXT NOT NULL CHECK (state IN ('not-started', 'in-progress', 'done')),
-  position_seconds REAL,
+  position_seconds DOUBLE PRECISION,
   updated_at TEXT NOT NULL,
   PRIMARY KEY (user_id, course_id, lesson_id)
 );
@@ -61,7 +61,7 @@ CREATE TABLE collection_courses (
   PRIMARY KEY (collection_id, course_id)
 );
 CREATE TABLE jobs (
-  id TEXT PRIMARY KEY, kind TEXT NOT NULL, status TEXT NOT NULL, progress REAL NOT NULL,
+  id TEXT PRIMARY KEY, kind TEXT NOT NULL, status TEXT NOT NULL, progress DOUBLE PRECISION NOT NULL,
   message TEXT, payload_json TEXT NOT NULL, result_json TEXT, error TEXT,
   created_at TEXT NOT NULL, updated_at TEXT NOT NULL
 );
diff --git a/packages/db/test/repos.test.ts b/packages/db/test/repos.test.ts
index 684b455..f84821c 100644
--- a/packages/db/test/repos.test.ts
+++ b/packages/db/test/repos.test.ts
@@ -14,7 +14,9 @@ forEachDb("progress upsert keeps one row", async (db) => {
   expect(got.l1.positionSeconds).toBeNull();
   expect(got.l2.positionSeconds).toBe(3);
   expect(typeof got.l1.updatedAt).toBe("string");
-  expect((await db.sql`SELECT COUNT(*) AS n FROM progress WHERE user_id = 'u'`)[0].n.toString()).toBe("2");
+  await p.set("u", "c", "l3", "in-progress", 1234.567);
+  expect((await p.get("u", "c")).l3.positionSeconds).toBe(1234.567);
+  expect((await db.sql`SELECT COUNT(*) AS n FROM progress WHERE user_id = 'u'`)[0].n.toString()).toBe("3");
 });
 
 forEachDb("notes order puts slide page 2 before page 10", async (db) => {

From 7f33169487432a1deae0310e77b950ac1f1d6d8d Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 03:04:46 +0100
Subject: [PATCH 13/14] feat(core): config, job queue, range media serving,
 feature composition

Adds aclRepo to @stc/db for canView.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 packages/core/src/app.ts          |  99 +++++++++++++++++++++++++++++
 packages/core/src/config.ts       |  22 +++++++
 packages/core/src/index.ts        |   4 ++
 packages/core/src/jobs.ts         |  69 ++++++++++++++++++++
 packages/core/src/media.ts        |  57 +++++++++++++++++
 packages/core/test/app.test.ts    | 101 ++++++++++++++++++++++++++++++
 packages/core/test/config.test.ts |  27 ++++++++
 packages/core/test/jobs.test.ts   |  61 ++++++++++++++++++
 packages/core/test/media.test.ts  |  59 +++++++++++++++++
 packages/db/src/index.ts          |   1 +
 packages/db/src/repos/acl.ts      |  16 +++++
 packages/db/test/acl.test.ts      |  17 +++++
 12 files changed, 533 insertions(+)
 create mode 100644 packages/core/src/app.ts
 create mode 100644 packages/core/src/config.ts
 create mode 100644 packages/core/src/index.ts
 create mode 100644 packages/core/src/jobs.ts
 create mode 100644 packages/core/src/media.ts
 create mode 100644 packages/core/test/app.test.ts
 create mode 100644 packages/core/test/config.test.ts
 create mode 100644 packages/core/test/jobs.test.ts
 create mode 100644 packages/core/test/media.test.ts
 create mode 100644 packages/db/src/repos/acl.ts
 create mode 100644 packages/db/test/acl.test.ts

diff --git a/packages/core/src/app.ts b/packages/core/src/app.ts
new file mode 100644
index 0000000..fc7554f
--- /dev/null
+++ b/packages/core/src/app.ts
@@ -0,0 +1,99 @@
+import type { AuthUser, Feature, RequestContext, RouteHandler, ServerContext } from "@stc/contracts";
+import type { LoadedCourse } from "@stc/course-format";
+import { aclRepo } from "@stc/db";
+import { serveMedia } from "./media";
+
+type Method = "GET" | "POST" | "PUT" | "PATCH" | "DELETE";
+export type Routes = Record<string, Partial<Record<Method, (req: Request) => Response | Promise<Response>>>>;
+
+export function canView(user: AuthUser | null, course: LoadedCourse, acl: { principal_type: string; principal_id: string }[], isAuthor = false): boolean {
+  const vis = course.manifest?.visibility ?? "restricted";
+  if (vis === "public") return true;
+  if (!user) return false;
+  if (vis === "signed-in") return true;
+  if (user.roles.includes("owner") || isAuthor) return true;
+  return acl.some((a) => (a.principal_type === "user" && a.principal_id === user.id) || (a.principal_type === "group" && user.groups.includes(a.principal_id)));
+}
+
+const json = (body: unknown, status = 200) => Response.json(body, { status });
+
+export function createApp(ctx: ServerContext, features: Feature[]): { routes: Routes; fetch(req: Request): Promise<Response> } {
+  const acl = aclRepo(ctx.db);
+
+  const core: Feature = {
+    name: "core",
+    routes: {
+      "/api/health": { GET: () => json({ ok: true, courses: ctx.courses.list().length, db: ctx.db.dialect }) },
+      "/api/media/:courseId/*": {
+        GET: async (req, rc) => {
+          // Parse from the pathname so we do not depend on how the server fills params for "*".
+          const m = /^\/api\/media\/([^/]+)\/(.*)$/s.exec(rc.url.pathname);
+          if (!m) return new Response("Not found", { status: 404 });
+          let courseId: string, rel: string;
+          try { courseId = decodeURIComponent(m[1]!); rel = decodeURIComponent(m[2]!); } catch { return new Response("Not found", { status: 404 }); }
+          const course = ctx.courses.get(courseId);
+          if (!course) return new Response("Not found", { status: 404 });
+          const visible = canView(rc.user, course, await acl.listForCourse(course.id), rc.user ? await acl.isAuthor(course.id, rc.user.id) : false);
+          if (!visible) return new Response("Not found", { status: 404 });
+          const abs = ctx.courses.resolvePath(course.id, rel);
+          if (!abs) return new Response("Not found", { status: 404 });
+          return serveMedia(req, abs, { download: rc.url.searchParams.has("download") });
+        },
+      },
+    },
+  };
+
+  const wrap = (h: RouteHandler) => async (req: Request & { params?: Record<string, string> }): Promise<Response> => {
+    const url = new URL(req.url);
+    const rc: RequestContext = { user: await ctx.auth.userFromRequest(req), params: req.params ?? {}, url };
+    return h(req, rc);
+  };
+
+  const routes: Routes = {};
+  for (const f of [core, ...features]) {
+    for (const [path, methods] of Object.entries(f.routes)) {
+      const slot = (routes[path] ??= {});
+      for (const [m, h] of Object.entries(methods) as [Method, RouteHandler][]) {
+        if (slot[m]) throw new Error(`Duplicate route ${m} ${path} (feature "${f.name}")`);
+        slot[m] = wrap(h);
+      }
+    }
+  }
+
+  // Matcher for fetch(): same semantics as Bun routes (":name" segment, trailing "*" wildcard).
+  const compiled = Object.entries(routes).map(([path, methods]) => {
+    const parts = path.split("/");
+    return { parts, methods };
+  });
+  const match = (pathname: string) => {
+    const segs = pathname.split("/");
+    for (const { parts, methods } of compiled) {
+      const params: Record<string, string> = {};
+      let ok = true;
+      for (let i = 0; i < parts.length && ok; i++) {
+        const p = parts[i]!;
+        if (p === "*") { params["*"] = segs.slice(i).join("/"); if (i >= segs.length) params["*"] = ""; return { methods, params }; }
+        if (segs[i] === undefined) ok = false;
+        else if (p.startsWith(":")) params[p.slice(1)] = decodeURIComponent(segs[i]!);
+        else if (p !== segs[i]) ok = false;
+      }
+      if (ok && parts.length === segs.length) return { methods, params };
+    }
+    return null;
+  };
+
+  return {
+    routes,
+    async fetch(req) {
+      const url = new URL(req.url);
+      let m: ReturnType<typeof match>;
+      try { m = match(url.pathname); } catch { return new Response("Bad request", { status: 400 }); }
+      if (!m) return new Response("Not found", { status: 404 });
+      const h = m.methods[req.method as Method];
+      if (!h) return new Response("Method not allowed", { status: 405 });
+      const r = req as Request & { params?: Record<string, string> };
+      r.params = m.params;
+      return h(r);
+    },
+  };
+}
diff --git a/packages/core/src/config.ts b/packages/core/src/config.ts
new file mode 100644
index 0000000..0359442
--- /dev/null
+++ b/packages/core/src/config.ts
@@ -0,0 +1,22 @@
+import type { AppConfig } from "@stc/contracts";
+
+const DEV_SECRET = "stc-dev-secret-change-me";
+
+export function loadConfig(env: Record<string, string | undefined> = process.env): AppConfig {
+  const port = env.STC_PORT !== undefined && env.STC_PORT !== "" ? Number(env.STC_PORT) : 3000;
+  if (!Number.isInteger(port) || port < 0) throw new Error(`Invalid STC_PORT: ${env.STC_PORT}`);
+  let secret = env.STC_SECRET;
+  if (!secret) {
+    if (env.NODE_ENV === "production") throw new Error("STC_SECRET is required when NODE_ENV=production");
+    console.warn("[stc] STC_SECRET is not set; using an insecure development default");
+    secret = DEV_SECRET;
+  }
+  return {
+    port,
+    databaseUrl: env.STC_DATABASE_URL || "sqlite://./data/stcourses.db",
+    dataDir: env.STC_DATA_DIR || "./data",
+    courseDirs: (env.STC_COURSE_DIRS || "./overlays:./courses").split(":").filter(Boolean),
+    secret,
+    publicUrl: env.STC_PUBLIC_URL || `http://localhost:${port}`,
+  };
+}
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
new file mode 100644
index 0000000..d955c36
--- /dev/null
+++ b/packages/core/src/index.ts
@@ -0,0 +1,4 @@
+export { loadConfig } from "./config";
+export { createJobQueue } from "./jobs";
+export { serveMedia, contentType, contentDisposition } from "./media";
+export { createApp, canView, type Routes } from "./app";
diff --git a/packages/core/src/jobs.ts b/packages/core/src/jobs.ts
new file mode 100644
index 0000000..21f365d
--- /dev/null
+++ b/packages/core/src/jobs.ts
@@ -0,0 +1,69 @@
+import type { JobHandler, JobQueue } from "@stc/contracts";
+import { jobsRepo, type Db } from "@stc/db";
+
+export function createJobQueue(db: Db, handlers: Record<string, JobHandler>, opts: { pollMs?: number } = {}): JobQueue & { start(): void; stop(): Promise<void> } {
+  const repo = jobsRepo(db);
+  const pollMs = opts.pollMs ?? 500;
+  const kinds = Object.keys(handlers);
+  let running = false;
+  let loop: Promise<void> | null = null;
+  let wake: (() => void) | null = null;
+  let abort = new AbortController();
+
+  const runOne = async (): Promise<boolean> => {
+    const job = await repo.claimNext(kinds);
+    if (!job) return false;
+    const jc = {
+      signal: abort.signal,
+      reportProgress: (fraction: number, message?: string) =>
+        repo.update(job.id, message === undefined ? { progress: fraction } : { progress: fraction, message }),
+    };
+    try {
+      const result = await handlers[job.kind]!(job.payload, jc);
+      await repo.update(job.id, { status: "done", progress: 1, result: result ?? null });
+    } catch (e) {
+      await repo.update(job.id, { status: "failed", error: e instanceof Error ? e.message : String(e) });
+    }
+    return true;
+  };
+
+  const sleep = () => new Promise<void>((res) => {
+    const t = setTimeout(res, pollMs);
+    wake = () => { clearTimeout(t); res(); };
+  });
+
+  const run = async () => {
+    while (running) {
+      let did = false;
+      try { did = await runOne(); } catch (e) { console.error("[stc] job worker error", e); }
+      if (!did && running) await sleep();
+    }
+  };
+
+  return {
+    async enqueue(kind, payload) {
+      const id = await repo.insert(kind, payload);
+      wake?.();
+      return id;
+    },
+    get: (id) => repo.get(id),
+    list: (kind) => repo.list(kind),
+    start() {
+      if (running) return;
+      running = true;
+      abort = new AbortController();
+      loop = (async () => {
+        // jobs left running by a previous process go back to the queue
+        await db.sql`UPDATE jobs SET status = 'queued', updated_at = ${new Date().toISOString()} WHERE status = 'running'`;
+        await run();
+      })();
+    },
+    async stop() {
+      running = false;
+      abort.abort();
+      wake?.();
+      await loop;
+      loop = null;
+    },
+  };
+}
diff --git a/packages/core/src/media.ts b/packages/core/src/media.ts
new file mode 100644
index 0000000..941c1ed
--- /dev/null
+++ b/packages/core/src/media.ts
@@ -0,0 +1,57 @@
+const TYPES: Record<string, string> = {
+  mp4: "video/mp4", webm: "video/webm", pdf: "application/pdf", png: "image/png", jpg: "image/jpeg", jpeg: "image/jpeg",
+  svg: "image/svg+xml", md: "text/markdown; charset=utf-8", txt: "text/plain; charset=utf-8", zip: "application/zip",
+  js: "text/javascript; charset=utf-8", ts: "text/plain; charset=utf-8",
+};
+
+export function contentType(path: string): string {
+  const ext = path.slice(path.lastIndexOf(".") + 1).toLowerCase();
+  return TYPES[ext] ?? "application/octet-stream";
+}
+
+/** RFC 6266 / 5987 header value: ASCII fallback plus UTF-8 filename*. */
+export function contentDisposition(name: string, kind: "inline" | "attachment" = "attachment"): string {
+  const fallback = name.replace(/[^\x20-\x7e]/g, "_").replace(/["\\]/g, "_");
+  const star = encodeURIComponent(name).replace(/['()*]/g, (c) => `%${c.charCodeAt(0).toString(16).toUpperCase()}`);
+  return `${kind}; filename="${fallback}"; filename*=UTF-8''${star}`;
+}
+
+function parseRange(header: string, size: number): { start: number; end: number } | "invalid" | null {
+  const m = /^bytes=(\d*)-(\d*)$/.exec(header.trim());
+  if (!m) return null; // malformed or multi-range: ignore, serve whole file
+  const [, a, b] = m;
+  if (a === "" && b === "") return null;
+  let start: number, end: number;
+  if (a === "") {
+    const n = Number(b);
+    if (n === 0) return "invalid";
+    start = Math.max(0, size - n); end = size - 1;
+  } else {
+    start = Number(a);
+    end = b === "" ? size - 1 : Math.min(Number(b), size - 1);
+    if (start >= size || start > end) return "invalid";
+  }
+  return { start, end };
+}
+
+export async function serveMedia(req: Request, absPath: string, opts: { download?: boolean } = {}): Promise<Response> {
+  const file = Bun.file(absPath);
+  if (!(await file.exists())) return new Response("Not found", { status: 404 });
+  const size = file.size;
+  const name = absPath.split("/").pop() ?? "file";
+  const headers: Record<string, string> = {
+    "Content-Type": contentType(absPath),
+    "Accept-Ranges": "bytes",
+  };
+  if (opts.download) headers["Content-Disposition"] = contentDisposition(name);
+  const range = req.headers.get("range");
+  const parsed = range ? parseRange(range, size) : null;
+  if (parsed === "invalid") return new Response(null, { status: 416, headers: { "Content-Range": `bytes */${size}`, "Accept-Ranges": "bytes" } });
+  if (!parsed) {
+    headers["Content-Length"] = String(size);
+    return new Response(req.method === "HEAD" ? null : file, { status: 200, headers });
+  }
+  headers["Content-Range"] = `bytes ${parsed.start}-${parsed.end}/${size}`;
+  headers["Content-Length"] = String(parsed.end - parsed.start + 1);
+  return new Response(req.method === "HEAD" ? null : file.slice(parsed.start, parsed.end + 1), { status: 206, headers });
+}
diff --git a/packages/core/test/app.test.ts b/packages/core/test/app.test.ts
new file mode 100644
index 0000000..6a8545c
--- /dev/null
+++ b/packages/core/test/app.test.ts
@@ -0,0 +1,101 @@
+import { expect, test } from "bun:test";
+import { cpSync, mkdirSync, mkdtempSync, symlinkSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join, resolve } from "node:path";
+import type { AuthUser, Feature, ServerContext } from "@stc/contracts";
+import { createCourseRepository } from "@stc/course-format";
+import { connect, migrate } from "@stc/db";
+import { canView, createApp } from "../src";
+
+const SAMPLE = resolve(import.meta.dir, "../../../fixtures/courses/sample");
+
+async function setup(user: AuthUser | null = null) {
+  const dir = mkdtempSync(join(tmpdir(), "stc-app-"));
+  cpSync(SAMPLE, join(dir, "pub"), { recursive: true });
+  const manifest = await Bun.file(join(SAMPLE, "stcourse.yaml")).text();
+  mkdirSync(join(dir, "priv"));
+  cpSync(SAMPLE, join(dir, "priv"), { recursive: true });
+  writeFileSync(join(dir, "priv/stcourse.yaml"), manifest.replace("id: sample", "id: secret").replace("visibility: public", "visibility: restricted"));
+  mkdirSync(join(dir, "broken"));
+  writeFileSync(join(dir, "broken/stcourse.yaml"), "schema: 1\nid: broken\ntitle: Broken\nroot: /does/not/exist\nmodules: []\n");
+  symlinkSync("/etc", join(dir, "pub/escape"));
+  const db = await connect("sqlite://:memory:");
+  await migrate(db);
+  const courses = await createCourseRepository([dir]);
+  const ctx = { db, courses, auth: { userFromRequest: async () => user } } as unknown as ServerContext;
+  return { ctx, db, dir };
+}
+const feat = (name: string): Feature => ({ name, routes: { "/api/x": { GET: () => new Response(name) } } });
+const user = (over: Partial<AuthUser> = {}): AuthUser => ({ id: "u1", email: "u@x", name: "U", roles: ["learner"], groups: [], ...over });
+
+test("health ok, and an error course does not break it", async () => {
+  const { ctx, db } = await setup();
+  expect(ctx.courses.get("broken")?.status).toBe("error");
+  const app = createApp(ctx, []);
+  const r = await app.fetch(new Request("http://x/api/health"));
+  expect(r.status).toBe(200);
+  expect(await r.json()).toEqual({ ok: true, courses: ctx.courses.list().length, db: "sqlite" });
+  expect(ctx.courses.list().length).toBe(3);
+  await db.close();
+});
+
+test("media serves a file with Range, and a missing/broken course is 404", async () => {
+  const { ctx, db } = await setup();
+  const app = createApp(ctx, []);
+  const r = await app.fetch(new Request("http://x/api/media/sample/media/clip.mp4", { headers: { Range: "bytes=0-9" } }));
+  expect(r.status).toBe(206);
+  expect((await app.fetch(new Request("http://x/api/media/broken/anything"))).status).toBe(404);
+  expect((await app.fetch(new Request("http://x/api/media/nope/a"))).status).toBe(404);
+  await db.close();
+});
+
+test("traversal, absolute and symlink escapes are 404", async () => {
+  const { ctx, db } = await setup();
+  const app = createApp(ctx, []);
+  for (const p of ["..%2F..%2Fetc%2Fpasswd", "%2Fetc%2Fpasswd", "escape/passwd", "../priv/stcourse.yaml", "%E0%A4%A"]) {
+    const r = await app.fetch(new Request(`http://x/api/media/sample/${p}`));
+    expect(r.status).toBe(404);
+  }
+  await db.close();
+});
+
+test("restricted course: 404 anonymous, visible to owner, author, ACL user and group", async () => {
+  const url = "http://x/api/media/secret/media/clip.mp4";
+  const run = async (u: AuthUser | null, seed?: (db: Awaited<ReturnType<typeof setup>>["db"]) => Promise<unknown>) => {
+    const { ctx, db } = await setup(u);
+    await seed?.(db);
+    const s = (await createApp(ctx, []).fetch(new Request(url))).status;
+    await db.close();
+    return s;
+  };
+  expect(await run(null)).toBe(404);
+  expect(await run(user())).toBe(404);
+  expect(await run(user({ roles: ["owner"] }))).toBe(200);
+  expect(await run(user(), (db) => db.sql`INSERT INTO course_authors (course_id, user_id) VALUES ('secret', 'u1')`)).toBe(200);
+  expect(await run(user(), (db) => db.sql`INSERT INTO course_acl VALUES ('secret', 'user', 'u1')`)).toBe(200);
+  expect(await run(user({ groups: ["g"] }), (db) => db.sql`INSERT INTO course_acl VALUES ('secret', 'group', 'g')`)).toBe(200);
+  expect(await run(user({ groups: ["h"] }), (db) => db.sql`INSERT INTO course_acl VALUES ('secret', 'group', 'g')`)).toBe(404);
+});
+
+test("duplicate method+path across features throws", async () => {
+  const { ctx, db } = await setup();
+  expect(() => createApp(ctx, [feat("a"), feat("b")])).toThrow(/Duplicate route GET \/api\/x/);
+  await db.close();
+});
+
+test("feature routes receive RequestContext with the user", async () => {
+  const u = user();
+  const { ctx, db } = await setup(u);
+  const f: Feature = { name: "a", routes: { "/api/who/:id": { GET: (_r, rc) => Response.json({ u: rc.user?.id, id: rc.params.id }) } } };
+  const app = createApp(ctx, [f]);
+  expect(await (await app.fetch(new Request("http://x/api/who/42"))).json()).toEqual({ u: "u1", id: "42" });
+  await db.close();
+});
+
+test("canView matrix", async () => {
+  const { ctx, db } = await setup();
+  const pub = ctx.courses.get("sample")!, priv = ctx.courses.get("secret")!;
+  expect(canView(null, pub, [])).toBe(true);
+  expect(canView(null, priv, [])).toBe(false);
+  await db.close();
+});
diff --git a/packages/core/test/config.test.ts b/packages/core/test/config.test.ts
new file mode 100644
index 0000000..3305ea7
--- /dev/null
+++ b/packages/core/test/config.test.ts
@@ -0,0 +1,27 @@
+import { expect, test, spyOn } from "bun:test";
+import { loadConfig } from "../src";
+
+test("defaults", () => {
+  const warn = spyOn(console, "warn").mockImplementation(() => {});
+  const c = loadConfig({});
+  expect(c.port).toBe(3000);
+  expect(c.databaseUrl).toBe("sqlite://./data/stcourses.db");
+  expect(c.dataDir).toBe("./data");
+  expect(c.courseDirs).toEqual(["./overlays", "./courses"]);
+  expect(c.publicUrl).toBe("http://localhost:3000");
+  expect(warn).toHaveBeenCalledTimes(1);
+  warn.mockRestore();
+});
+
+test("colon splitting and overrides", () => {
+  const c = loadConfig({ STC_PORT: "8080", STC_COURSE_DIRS: "/a b:/c", STC_SECRET: "s", STC_PUBLIC_URL: "https://x.test" });
+  expect(c.port).toBe(8080);
+  expect(c.courseDirs).toEqual(["/a b", "/c"]);
+  expect(c.secret).toBe("s");
+  expect(c.publicUrl).toBe("https://x.test");
+});
+
+test("production without a secret throws", () => {
+  expect(() => loadConfig({ NODE_ENV: "production" })).toThrow(/STC_SECRET/);
+  expect(loadConfig({ NODE_ENV: "production", STC_SECRET: "x" }).secret).toBe("x");
+});
diff --git a/packages/core/test/jobs.test.ts b/packages/core/test/jobs.test.ts
new file mode 100644
index 0000000..d65a5ad
--- /dev/null
+++ b/packages/core/test/jobs.test.ts
@@ -0,0 +1,61 @@
+import { expect } from "bun:test";
+import { forEachDb } from "../../db/test/helpers";
+import { jobsRepo } from "@stc/db";
+import { createJobQueue } from "../src";
+
+const until = async (f: () => Promise<boolean>) => {
+  for (let i = 0; i < 200; i++) { if (await f()) return; await Bun.sleep(10); }
+  throw new Error("timeout");
+};
+
+forEachDb("job runs to done with result and persisted progress", async (db) => {
+  const q = createJobQueue(db, {
+    ok: async (p, jc) => { await jc.reportProgress(0.5, "half"); return { echoed: p }; },
+  }, { pollMs: 10 });
+  q.start();
+  try {
+    const id = await q.enqueue("ok", { a: 1 });
+    await until(async () => (await q.get(id))?.status === "done");
+    const j = (await q.get(id))!;
+    expect(j.result).toEqual({ echoed: { a: 1 } });
+    expect(j.message).toBe("half");
+    expect(j.progress).toBe(1);
+  } finally { await q.stop(); }
+});
+
+forEachDb("throwing handler gives failed with message", async (db) => {
+  const q = createJobQueue(db, { bad: async () => { throw new Error("boom"); } }, { pollMs: 10 });
+  q.start();
+  try {
+    const id = await q.enqueue("bad", null);
+    await until(async () => (await q.get(id))?.status === "failed");
+    expect((await q.get(id))!.error).toBe("boom");
+  } finally { await q.stop(); }
+});
+
+forEachDb("progress updates persist while running", async (db) => {
+  let release!: () => void;
+  const gate = new Promise<void>((r) => (release = r));
+  const q = createJobQueue(db, { slow: async (_p, jc) => { await jc.reportProgress(0.3, "working"); await gate; return 1; } }, { pollMs: 10 });
+  q.start();
+  try {
+    const id = await q.enqueue("slow", null);
+    await until(async () => (await q.get(id))?.progress === 0.3);
+    expect((await q.get(id))!.status).toBe("running");
+    expect((await q.get(id))!.message).toBe("working");
+    release();
+    await until(async () => (await q.get(id))?.status === "done");
+  } finally { release(); await q.stop(); }
+});
+
+forEachDb("stale running job is requeued at start", async (db) => {
+  const id = await jobsRepo(db).insert("ok", { z: 1 });
+  await jobsRepo(db).claimNext(["ok"]);
+  expect((await jobsRepo(db).get(id))!.status).toBe("running");
+  const q = createJobQueue(db, { ok: async () => "again" }, { pollMs: 10 });
+  q.start();
+  try {
+    await until(async () => (await q.get(id))?.status === "done");
+    expect((await q.get(id))!.result).toBe("again");
+  } finally { await q.stop(); }
+});
diff --git a/packages/core/test/media.test.ts b/packages/core/test/media.test.ts
new file mode 100644
index 0000000..10fdb74
--- /dev/null
+++ b/packages/core/test/media.test.ts
@@ -0,0 +1,59 @@
+import { expect, test } from "bun:test";
+import { mkdtempSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { serveMedia } from "../src";
+
+const dir = mkdtempSync(join(tmpdir(), "stc-media-"));
+const file = join(dir, "clip.mp4");
+const bytes = new Uint8Array(1000).map((_, i) => i % 251);
+writeFileSync(file, bytes);
+const req = (range?: string) => new Request("http://x/m", { headers: range ? { Range: range } : {} });
+
+test("full file gives 200", async () => {
+  const r = await serveMedia(req(), file);
+  expect(r.status).toBe(200);
+  expect(r.headers.get("content-type")).toBe("video/mp4");
+  expect(r.headers.get("accept-ranges")).toBe("bytes");
+  expect(r.headers.get("content-length")).toBe("1000");
+  expect((await r.arrayBuffer()).byteLength).toBe(1000);
+});
+
+test("bytes=0-99 gives 206 with Content-Range", async () => {
+  const r = await serveMedia(req("bytes=0-99"), file);
+  expect(r.status).toBe(206);
+  expect(r.headers.get("content-range")).toBe("bytes 0-99/1000");
+  expect(r.headers.get("content-length")).toBe("100");
+  expect(new Uint8Array(await r.arrayBuffer())).toEqual(bytes.slice(0, 100));
+});
+
+test("open-ended, suffix and clamped ranges", async () => {
+  let r = await serveMedia(req("bytes=900-"), file);
+  expect(r.status).toBe(206);
+  expect(r.headers.get("content-range")).toBe("bytes 900-999/1000");
+  r = await serveMedia(req("bytes=-10"), file);
+  expect(r.headers.get("content-range")).toBe("bytes 990-999/1000");
+  expect(new Uint8Array(await r.arrayBuffer())).toEqual(bytes.slice(990));
+  r = await serveMedia(req("bytes=990-5000"), file);
+  expect(r.headers.get("content-range")).toBe("bytes 990-999/1000");
+});
+
+test("unsatisfiable range gives 416", async () => {
+  const r = await serveMedia(req("bytes=999999999-"), file);
+  expect(r.status).toBe(416);
+  expect(r.headers.get("content-range")).toBe("bytes */1000");
+});
+
+test("non-ASCII filename gets a valid filename*", async () => {
+  const f = join(dir, "Æble notes.pdf");
+  writeFileSync(f, "pdf");
+  const r = await serveMedia(req(), f, { download: true });
+  expect(r.headers.get("content-type")).toBe("application/pdf");
+  const cd = r.headers.get("content-disposition")!;
+  expect(cd).toContain("filename*=UTF-8''%C3%86ble%20notes.pdf");
+  expect(cd).toContain('filename="_ble notes.pdf"');
+});
+
+test("missing file is 404", async () => {
+  expect((await serveMedia(req(), join(dir, "nope.mp4"))).status).toBe(404);
+});
diff --git a/packages/db/src/index.ts b/packages/db/src/index.ts
index 7dba514..ec4d4e5 100644
--- a/packages/db/src/index.ts
+++ b/packages/db/src/index.ts
@@ -5,3 +5,4 @@ export { notesRepo, type Note, type NoteInput } from "./repos/notes";
 export { attemptsRepo, type Attempt } from "./repos/attempts";
 export { libraryRepo, type Collection } from "./repos/library";
 export { jobsRepo, type JobPatch } from "./repos/jobs";
+export { aclRepo, type AclEntry } from "./repos/acl";
diff --git a/packages/db/src/repos/acl.ts b/packages/db/src/repos/acl.ts
new file mode 100644
index 0000000..d5ccd50
--- /dev/null
+++ b/packages/db/src/repos/acl.ts
@@ -0,0 +1,16 @@
+import type { Db } from "../connect";
+
+export interface AclEntry { principal_type: "user" | "group"; principal_id: string }
+
+export function aclRepo(db: Db) {
+  return {
+    async listForCourse(courseId: string): Promise<AclEntry[]> {
+      const rows = await db.sql`SELECT principal_type, principal_id FROM course_acl WHERE course_id = ${courseId} ORDER BY principal_type, principal_id`;
+      return rows.map((r: AclEntry) => ({ principal_type: r.principal_type, principal_id: r.principal_id }));
+    },
+    async isAuthor(courseId: string, userId: string): Promise<boolean> {
+      const rows = await db.sql`SELECT 1 AS x FROM course_authors WHERE course_id = ${courseId} AND user_id = ${userId}`;
+      return rows.length > 0;
+    },
+  };
+}
diff --git a/packages/db/test/acl.test.ts b/packages/db/test/acl.test.ts
new file mode 100644
index 0000000..ad0c6fc
--- /dev/null
+++ b/packages/db/test/acl.test.ts
@@ -0,0 +1,17 @@
+import { expect } from "bun:test";
+import { forEachDb } from "./helpers";
+import { aclRepo } from "../src";
+
+forEachDb("aclRepo lists ACL rows and detects authors", async (db) => {
+  await db.sql`INSERT INTO course_acl (course_id, principal_type, principal_id) VALUES ('c', 'user', 'u1'), ('c', 'group', 'g1'), ('d', 'user', 'u2')`;
+  await db.sql`INSERT INTO course_authors (course_id, user_id) VALUES ('c', 'a1')`;
+  const r = aclRepo(db);
+  expect(await r.listForCourse("c")).toEqual([
+    { principal_type: "group", principal_id: "g1" },
+    { principal_type: "user", principal_id: "u1" },
+  ]);
+  expect(await r.listForCourse("none")).toEqual([]);
+  expect(await r.isAuthor("c", "a1")).toBe(true);
+  expect(await r.isAuthor("c", "u1")).toBe(false);
+  expect(await r.isAuthor("d", "a1")).toBe(false);
+});

From 05eee4cd4086aacf02b3718621b2ba5d42491fb3 Mon Sep 17 00:00:00 2001
From: Lucas Winther <lucwin@ece.au.dk>
Date: Fri, 30 Oct 2026 03:05:49 +0100
Subject: [PATCH 14/14] feat: server entry and web shell with design tokens

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 apps/server/src/main.ts              | 44 +++++++++++++++++++++
 apps/server/test/server.test.ts      | 36 +++++++++++++++++
 apps/web/index.html                  | 14 +++++++
 apps/web/src/features.ts             |  4 ++
 apps/web/src/main.tsx                | 39 ++++++++++++++++++
 bun.lock                             | 29 ++++++++++++++
 package.json                         |  9 +++++
 packages/ui/src/AppShell.tsx         | 13 ++++++
 packages/ui/src/fonts.css            |  7 ++++
 packages/ui/src/index.ts             |  2 +
 packages/ui/src/primitives.tsx       | 46 ++++++++++++++++++++++
 packages/ui/src/tokens.css           | 59 ++++++++++++++++++++++++++++
 packages/ui/test/primitives.test.tsx | 19 +++++++++
 13 files changed, 321 insertions(+)
 create mode 100644 apps/server/src/main.ts
 create mode 100644 apps/server/test/server.test.ts
 create mode 100644 apps/web/index.html
 create mode 100644 apps/web/src/features.ts
 create mode 100644 apps/web/src/main.tsx
 create mode 100644 packages/ui/src/AppShell.tsx
 create mode 100644 packages/ui/src/fonts.css
 create mode 100644 packages/ui/src/index.ts
 create mode 100644 packages/ui/src/primitives.tsx
 create mode 100644 packages/ui/src/tokens.css
 create mode 100644 packages/ui/test/primitives.test.tsx

diff --git a/apps/server/src/main.ts b/apps/server/src/main.ts
new file mode 100644
index 0000000..9b43b71
--- /dev/null
+++ b/apps/server/src/main.ts
@@ -0,0 +1,44 @@
+import type { AppConfig, AuthService, Feature, JobHandler, ServerContext } from "@stc/contracts";
+import { createApp, createJobQueue, loadConfig } from "@stc/core";
+import { createCourseRepository } from "@stc/course-format";
+import { connect, migrate } from "@stc/db";
+import indexHtml from "../../web/index.html";
+
+// Temporary: the learner package replaces this with real sessions.
+const anonymousAuth: AuthService = { userFromRequest: async () => null };
+
+export async function startServer(
+  config: AppConfig,
+  features: Feature[],
+  _webFeatures?: unknown,
+): Promise<{ server: Bun.Server<undefined>; stop(): Promise<void> }> {
+  const db = await connect(config.databaseUrl);
+  await migrate(db);
+  const courses = await createCourseRepository(config.courseDirs);
+  const handlers: Record<string, JobHandler> = {};
+  for (const f of features) Object.assign(handlers, f.jobs);
+  const jobs = createJobQueue(db, handlers);
+  const ctx: ServerContext = { config, db, courses, jobs, auth: anonymousAuth };
+  const app = createApp(ctx, features);
+  jobs.start();
+  const server = Bun.serve({
+    port: config.port,
+    // Bun routes win over fetch; "/api/*" falls through to the composed app (404 for unknown API paths).
+    routes: { ...app.routes, "/api/*": (req) => app.fetch(req), "/*": indexHtml },
+    fetch: (req) => app.fetch(req),
+  });
+  return {
+    server,
+    async stop() {
+      await server.stop(true);
+      await jobs.stop();
+      await db.close();
+    },
+  };
+}
+
+if (import.meta.main) {
+  const config = loadConfig();
+  const { server } = await startServer(config, []);
+  console.log(`STCourses listening on ${server.url}`);
+}
diff --git a/apps/server/test/server.test.ts b/apps/server/test/server.test.ts
new file mode 100644
index 0000000..8f17abb
--- /dev/null
+++ b/apps/server/test/server.test.ts
@@ -0,0 +1,36 @@
+import { afterAll, beforeAll, expect, test } from "bun:test";
+import { resolve } from "node:path";
+import { loadConfig } from "@stc/core";
+import { startServer } from "../src/main";
+
+let s: Awaited<ReturnType<typeof startServer>>;
+let base: string;
+beforeAll(async () => {
+  const config = loadConfig({
+    STC_PORT: "0", STC_DATABASE_URL: "sqlite://:memory:", STC_SECRET: "t",
+    STC_COURSE_DIRS: resolve(import.meta.dir, "../../../fixtures/courses"),
+  });
+  s = await startServer(config, []);
+  base = s.server.url.toString().replace(/\/$/, "");
+});
+afterAll(() => s.stop());
+
+test("health reports the fixture course", async () => {
+  expect(await (await fetch(`${base}/api/health`)).json()).toEqual({ ok: true, courses: 1, db: "sqlite" });
+});
+
+test("SPA paths return the HTML shell", async () => {
+  const r = await fetch(`${base}/some/spa/path`);
+  expect(r.status).toBe(200);
+  expect(await r.text()).toContain('<div id="root">');
+});
+
+test("unknown API paths are 404, not the SPA", async () => {
+  expect((await fetch(`${base}/api/nope`)).status).toBe(404);
+});
+
+test("media honours Range", async () => {
+  const r = await fetch(`${base}/api/media/sample/media/clip.mp4`, { headers: { Range: "bytes=0-9" } });
+  expect(r.status).toBe(206);
+  expect((await r.arrayBuffer()).byteLength).toBe(10);
+});
diff --git a/apps/web/index.html b/apps/web/index.html
new file mode 100644
index 0000000..2d79c9a
--- /dev/null
+++ b/apps/web/index.html
@@ -0,0 +1,14 @@
+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <title>STCourses</title>
+  <link rel="stylesheet" href="../../packages/ui/src/fonts.css">
+  <link rel="stylesheet" href="../../packages/ui/src/tokens.css">
+</head>
+<body>
+  <div id="root"></div>
+  <script type="module" src="./src/main.tsx"></script>
+</body>
+</html>
diff --git a/apps/web/src/features.ts b/apps/web/src/features.ts
new file mode 100644
index 0000000..8b077c9
--- /dev/null
+++ b/apps/web/src/features.ts
@@ -0,0 +1,4 @@
+import type { WebFeature } from "@stc/contracts";
+
+// Phase 1 packages append one import line each and push into this list.
+export const webFeatures: WebFeature[] = [];
diff --git a/apps/web/src/main.tsx b/apps/web/src/main.tsx
new file mode 100644
index 0000000..a9afe98
--- /dev/null
+++ b/apps/web/src/main.tsx
@@ -0,0 +1,39 @@
+import { createRoot } from "react-dom/client";
+import { lazy, Suspense } from "react";
+import { createBrowserRouter, Link, Outlet, RouterProvider, type RouteObject } from "react-router-dom";
+import { AppShell } from "@stc/ui";
+import { webFeatures } from "./features";
+
+function Home() {
+  return <p className="work">No features installed yet</p>;
+}
+
+function Layout() {
+  const nav = webFeatures.flatMap((f) => f.routes.filter((r) => r.nav?.area === "header"));
+  const header = (
+    <>
+      <Link to="/" style={{ fontWeight: 600, color: "var(--head)", textDecoration: "none" }}>STCourses</Link>
+      <nav style={{ display: "flex", gap: 14 }}>
+        {nav.map((r) => <Link key={r.path} to={r.path}>{r.nav!.label}</Link>)}
+      </nav>
+    </>
+  );
+  return (
+    <AppShell header={header}>
+      <Suspense fallback={null}><Outlet /></Suspense>
+    </AppShell>
+  );
+}
+
+const featureRoutes: RouteObject[] = webFeatures.flatMap((f) =>
+  f.routes.map((r) => {
+    const Element = lazy(r.element);
+    return { path: r.path, element: <Element /> };
+  }),
+);
+
+const router = createBrowserRouter([
+  { element: <Layout />, children: [...featureRoutes, ...(featureRoutes.some((r) => r.path === "/") ? [] : [{ path: "*", element: <Home /> }])] },
+]);
+
+createRoot(document.getElementById("root")!).render(<RouterProvider router={router} />);
diff --git a/bun.lock b/bun.lock
index 736e0ae..15e30fe 100644
--- a/bun.lock
+++ b/bun.lock
@@ -4,8 +4,17 @@
   "workspaces": {
     "": {
       "name": "stcourses",
+      "dependencies": {
+        "@fontsource/ibm-plex-mono": "^5.3.0",
+        "@fontsource/ibm-plex-sans": "^5.3.0",
+        "@fontsource/literata": "^5.3.0",
+        "react": "^19.3.1",
+        "react-dom": "^19.3.1",
+        "react-router-dom": "6",
+      },
       "devDependencies": {
         "@types/react": "^19",
+        "@types/react-dom": "^19.3.0",
         "bun-types": "^1.3.14",
         "typescript": "^5",
       },
@@ -59,6 +68,14 @@
     },
   },
   "packages": {
+    "@fontsource/ibm-plex-mono": ["@fontsource/ibm-plex-mono@5.3.0", "", {}, "sha512-eTgnZjZEGk1QtD3ZstF+Vclo2HLAni8YMy34/DxllwZvyz1lR/1RF/xTiAquOBO7MvqBx8D2Ig2WCPMVfdZu7Q=="],
+
+    "@fontsource/ibm-plex-sans": ["@fontsource/ibm-plex-sans@5.3.0", "", {}, "sha512-CbE4CbbEEZJX860XyUiRpsksXIQR8Rp2XDva2VO53NJox9tVNtusrysd2x5YkUEY3ErQ66W1IiiQL8/wihhw5w=="],
+
+    "@fontsource/literata": ["@fontsource/literata@5.3.0", "", {}, "sha512-9JGMT5+YfBK49thoMq9ASaMRJErHT4V4QuMhAEwKHRLreOsIMP2xP6ZRLhPJ0e6YlET+kjWTJuN7LAxt9/gWGQ=="],
+
+    "@remix-run/router": ["@remix-run/router@1.23.4", "", {}, "sha512-q7j5geK7xs3UJSdm9/iytUNclBnLmYx1EnSeCFXHPeutdqgIMeFeHtUZgS3EhlKxdBEAu8OwtJCwmLrEzpSs7Q=="],
+
     "@stc/contracts": ["@stc/contracts@workspace:packages/contracts"],
 
     "@stc/core": ["@stc/core@workspace:packages/core"],
@@ -85,10 +102,22 @@
 
     "@types/react": ["@types/react@19.3.0", "", { "dependencies": { "csstype": "^3.2.2" } }, "sha512-N0rFCuH9YoxG9/m61l9MfpJKfmLOVU0em7ipIz6TRgSSkvReLB9vL85GB+yr8Bs5leqpvg96JSwF4ZS1s4viQg=="],
 
+    "@types/react-dom": ["@types/react-dom@19.3.0", "", { "peerDependencies": { "@types/react": "^19.3.0" } }, "sha512-ZI7bU42mZXXKHn/qNLEw2IrbiINU7X5+vfgdixBHkCNpYWXjKgfQ/P+uyGb5CjOLB9UcnTeg3rylQtV2hym44Q=="],
+
     "bun-types": ["bun-types@1.4.4", "", { "dependencies": { "@types/node": "*", "undici-types": "*" } }, "sha512-yjrJh5oGX7mMPKGd19YXyIjmEuj4G4zNC30bs7PM9Az7NQ3ndF3j6hbeRdvJTRQEhJ/FYQwW0a2moweEi2hMxQ=="],
 
     "csstype": ["csstype@3.2.3", "", {}, "sha512-z1HGKcYy2xA8AGQfwrn0PAy+PB7X/GSj3UVJW9qKyn43xWa+gl5nXmU4qqLMRzWVLFC8KusUX8T/0kCiOYpAIQ=="],
 
+    "react": ["react@19.3.1", "", {}, "sha512-QNhWdt7nrgVWWQG58QuGsAR3jv3Hbe4mb4vz7w2csnHavciZJgda1CPNaldF6eVxv90ud3jUXpKlHL69gO38yw=="],
+
+    "react-dom": ["react-dom@19.3.1", "", { "dependencies": { "scheduler": "^0.28.0" }, "peerDependencies": { "react": "^19.3.1" } }, "sha512-Y0bARz53lhEC1NMCASs0/j+faB/zqt3R8hpvg1e8+61ZVJ4UL0UdC4cBbXfZMcIuhrfgeILTLe+ZeBCavQPtKQ=="],
+
+    "react-router": ["react-router@6.30.6", "", { "dependencies": { "@remix-run/router": "1.23.4" }, "peerDependencies": { "react": ">=16.8" } }, "sha512-5HfK7k5im7LTOB0EqCQmfvy4C13G92Ssj1VTmouTK3AJvyjKTnFuCV0vcMAD/JS+JC4DvDIBRrlAeJIFjh5VWg=="],
+
+    "react-router-dom": ["react-router-dom@6.30.6", "", { "dependencies": { "@remix-run/router": "1.23.4", "react-router": "6.30.6" }, "peerDependencies": { "react": ">=16.8", "react-dom": ">=16.8" } }, "sha512-0RHKZz7wwffvkU+2MFVT2NnjK44ssLEV+m0CAJaS2Ksmorrwj7WxH00jO0SOCW26/tINUnJHToXblDs33I38YQ=="],
+
+    "scheduler": ["scheduler@0.28.0", "", {}, "sha512-juorfCmIkIw8tT+p5BXSm6PJjQF/ycEYmKyzURCIt/RaZIhL+PulbQ9Yu2z1HdOJDdqDTlxA1+xKBmHXJsczAw=="],
+
     "typescript": ["typescript@5.9.3", "", { "bin": { "tsc": "bin/tsc", "tsserver": "bin/tsserver" } }, "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw=="],
 
     "undici-types": ["undici-types@8.12.3", "", {}, "sha512-EXE4ydL3S76dFb27UFjNVZHTyv/TLdATj/KUe29ptdcg6qXL48J2tZ3126E5kICj5jn781OR+XlVH1N6Mz8jbA=="],
diff --git a/package.json b/package.json
index 341e6f2..87fe586 100644
--- a/package.json
+++ b/package.json
@@ -10,7 +10,16 @@
   },
   "devDependencies": {
     "@types/react": "^19",
+    "@types/react-dom": "^19.3.0",
     "bun-types": "^1.3.14",
     "typescript": "^5"
+  },
+  "dependencies": {
+    "@fontsource/ibm-plex-mono": "^5.3.0",
+    "@fontsource/ibm-plex-sans": "^5.3.0",
+    "@fontsource/literata": "^5.3.0",
+    "react": "^19.3.1",
+    "react-dom": "^19.3.1",
+    "react-router-dom": "6"
   }
 }
diff --git a/packages/ui/src/AppShell.tsx b/packages/ui/src/AppShell.tsx
new file mode 100644
index 0000000..31e23d6
--- /dev/null
+++ b/packages/ui/src/AppShell.tsx
@@ -0,0 +1,13 @@
+import type { ReactNode } from "react";
+
+export function AppShell({ header, sidebar, children }: { header?: ReactNode; sidebar?: ReactNode; children: ReactNode }) {
+  return (
+    <>
+      {header ? <header className="stc-top">{header}</header> : null}
+      <div className="stc-shell">
+        {sidebar ? <aside className="stc-side">{sidebar}</aside> : null}
+        <main className="stc-main">{children}</main>
+      </div>
+    </>
+  );
+}
diff --git a/packages/ui/src/fonts.css b/packages/ui/src/fonts.css
new file mode 100644
index 0000000..0bd8525
--- /dev/null
+++ b/packages/ui/src/fonts.css
@@ -0,0 +1,7 @@
+@import "@fontsource/ibm-plex-sans/400.css";
+@import "@fontsource/ibm-plex-sans/500.css";
+@import "@fontsource/ibm-plex-sans/600.css";
+@import "@fontsource/ibm-plex-mono/400.css";
+@import "@fontsource/literata/400.css";
+@import "@fontsource/literata/600.css";
+@import "@fontsource/literata/400-italic.css";
diff --git a/packages/ui/src/index.ts b/packages/ui/src/index.ts
new file mode 100644
index 0000000..11877ed
--- /dev/null
+++ b/packages/ui/src/index.ts
@@ -0,0 +1,2 @@
+export { AppShell } from "./AppShell";
+export { Pill, SegmentedToggle, ProgressBar, FloatingActionBar, CourseCover, monogram } from "./primitives";
diff --git a/packages/ui/src/primitives.tsx b/packages/ui/src/primitives.tsx
new file mode 100644
index 0000000..efa08a4
--- /dev/null
+++ b/packages/ui/src/primitives.tsx
@@ -0,0 +1,46 @@
+import type { ButtonHTMLAttributes, CSSProperties, ReactNode } from "react";
+
+export function Pill({ variant = "default", className, ...rest }: { variant?: "default" | "primary" | "ghost" } & ButtonHTMLAttributes<HTMLButtonElement>) {
+  const cls = ["stc-pill", variant !== "default" && `stc-pill--${variant}`, className].filter(Boolean).join(" ");
+  return <button type="button" {...rest} className={cls} />;
+}
+
+export function SegmentedToggle({ options, value, onChange, label }: {
+  options: { value: string; label: string }[]; value: string; onChange: (v: string) => void; label: string;
+}) {
+  return (
+    <div className="stc-seg" role="group" aria-label={label}>
+      {options.map((o) => (
+        <button key={o.value} type="button" aria-pressed={o.value === value} onClick={() => onChange(o.value)}>{o.label}</button>
+      ))}
+    </div>
+  );
+}
+
+export function ProgressBar({ value, dim, label }: { value: number; dim?: boolean; label: string }) {
+  const pct = Math.round(Math.min(1, Math.max(0, value)) * 100);
+  return (
+    <span className={dim ? "stc-bar stc-bar--dim" : "stc-bar"} role="progressbar" aria-label={label} aria-valuemin={0} aria-valuemax={100} aria-valuenow={pct}>
+      <i style={{ width: `${pct}%` }} />
+    </span>
+  );
+}
+
+export function FloatingActionBar({ children }: { children: ReactNode }) {
+  return <div className="stc-dock" role="toolbar">{children}</div>;
+}
+
+export function monogram(title: string): string {
+  const words = title.trim().split(/\s+/).filter(Boolean);
+  const letters = words.length >= 2 ? [words[0]![0], words[1]![0]] : Array.from(words[0] ?? "?").slice(0, 2);
+  return letters.join("").toUpperCase();
+}
+
+export function CourseCover({ title, image, accent }: { title: string; image?: string; accent?: string }) {
+  const style = accent ? ({ "--cfg": accent } as CSSProperties) : undefined;
+  return (
+    <div className="stc-cover" style={style} role="img" aria-label={title}>
+      {image ? <img src={image} alt="" /> : <span aria-hidden="true">{monogram(title)}</span>}
+    </div>
+  );
+}
diff --git a/packages/ui/src/tokens.css b/packages/ui/src/tokens.css
new file mode 100644
index 0000000..b0beebb
--- /dev/null
+++ b/packages/ui/src/tokens.css
@@ -0,0 +1,59 @@
+:root {
+  --ground: #12141a; --side: #181b22; --raised: #232733; --line: #262a33; --line2: #343947;
+  --text: #d9dce3; --read: #d9d4c8; --head: #f2efe8; --muted: #a4abb8; --faint: #8c93a0;
+  --accent: #f1b44c; --accent-dim: #8c7440; --on-accent: #12141a;
+  --ok: #86c79f; --bad: #ee8f8f;
+  --sans: "IBM Plex Sans", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
+  --serif: "Literata", Georgia, "Times New Roman", serif;
+  --mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
+  --top: 52px; --sidew: 296px; --fast: 140ms;
+  color-scheme: dark;
+}
+*, *::before, *::after { box-sizing: border-box; }
+body { margin: 0; background: var(--ground); color: var(--text); font: 400 14px/1.5 var(--sans); -webkit-font-smoothing: antialiased; }
+a { color: inherit; }
+button, input, textarea { font: inherit; color: inherit; }
+button { cursor: pointer; }
+code, pre { font-family: var(--mono); }
+:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
+::selection { background: color-mix(in srgb, var(--accent) 35%, transparent); }
+.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
+
+.reading { font-family: var(--serif); font-size: 19px; line-height: 1.75; color: var(--read); max-width: 660px; }
+.work { font-family: var(--sans); font-size: 15.5px; line-height: 1.6; color: var(--text); max-width: 760px; }
+
+/* shell */
+.stc-top { position: sticky; top: 0; z-index: 30; height: var(--top); display: flex; align-items: center; gap: 14px; padding: 0 16px; background: var(--ground); border-bottom: 1px solid var(--line); }
+.stc-shell { display: flex; align-items: flex-start; }
+.stc-side { position: sticky; top: var(--top); flex: none; width: var(--sidew); height: calc(100vh - var(--top)); overflow-y: auto; background: var(--side); border-right: 1px solid var(--line); }
+.stc-main { flex: 1; min-width: 0; padding: 44px 40px 0; }
+
+/* pill */
+.stc-pill { display: inline-flex; align-items: center; gap: 8px; height: 34px; padding: 0 15px; border: 1px solid var(--line2); border-radius: 18px; background: none; font-size: 13px; font-weight: 500; text-decoration: none; white-space: nowrap; transition: background var(--fast), color var(--fast), border-color var(--fast); }
+.stc-pill:hover { background: var(--raised); }
+.stc-pill--primary { background: var(--accent); border-color: var(--accent); color: var(--on-accent); }
+.stc-pill--primary:hover { background: color-mix(in srgb, var(--accent) 86%, #fff); }
+.stc-pill--ghost { border-color: transparent; color: var(--muted); }
+.stc-pill--ghost:hover { color: var(--text); }
+.stc-pill:disabled { opacity: .45; cursor: default; }
+
+/* segmented toggle */
+.stc-seg { display: inline-flex; padding: 2px; border: 1px solid var(--line2); border-radius: 20px; flex: none; }
+.stc-seg button { border: 0; background: none; height: 28px; padding: 0 13px; border-radius: 16px; font-size: 12.5px; font-weight: 500; color: var(--faint); transition: background var(--fast), color var(--fast); }
+.stc-seg button:hover { color: var(--text); }
+.stc-seg button[aria-pressed="true"] { background: var(--raised); color: var(--head); }
+
+/* progress */
+.stc-bar { display: block; flex: 1; height: 4px; border-radius: 2px; background: var(--line); overflow: hidden; }
+.stc-bar > i { display: block; height: 100%; background: var(--accent); border-radius: 2px; }
+.stc-bar--dim > i { background: var(--accent-dim); }
+
+/* floating action bar */
+.stc-dock { position: sticky; bottom: 18px; z-index: 10; display: flex; width: max-content; max-width: 100%; margin: 56px auto 18px; gap: 4px; padding: 5px; background: var(--raised); border: 1px solid var(--line2); border-radius: 24px; box-shadow: 0 0 0 10px var(--ground); }
+.stc-dock .stc-pill { height: 36px; border-color: transparent; }
+.stc-dock .stc-pill:hover { background: var(--line2); }
+.stc-dock .stc-pill--primary:hover { background: color-mix(in srgb, var(--accent) 86%, #fff); }
+
+/* cover */
+.stc-cover { flex: none; position: relative; width: var(--cw, 44px); aspect-ratio: 3 / 4; border-radius: 6px; background: var(--cbg, var(--raised)); color: var(--cfg, var(--accent)); border: 1px solid color-mix(in srgb, var(--cfg, var(--accent)) 18%, transparent); overflow: hidden; font: 600 calc(var(--cw, 44px) * .34) / 1 var(--sans); letter-spacing: -.03em; display: flex; align-items: flex-end; padding: calc(var(--cw, 44px) * .12); }
+.stc-cover img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; }
diff --git a/packages/ui/test/primitives.test.tsx b/packages/ui/test/primitives.test.tsx
new file mode 100644
index 0000000..775fbf1
--- /dev/null
+++ b/packages/ui/test/primitives.test.tsx
@@ -0,0 +1,19 @@
+import { expect, test } from "bun:test";
+import { renderToString } from "react-dom/server";
+import { CourseCover, ProgressBar, SegmentedToggle } from "../src";
+
+test("ProgressBar exposes aria-valuenow as a percentage", () => {
+  const html = renderToString(<ProgressBar value={0.4} label="Course progress" />);
+  expect(html).toContain('role="progressbar"');
+  expect(html).toContain('aria-valuenow="40"');
+});
+
+test("CourseCover without an image shows a two-letter monogram", () => {
+  expect(renderToString(<CourseCover title="Pure Snake" />)).toContain(">PS<");
+  expect(renderToString(<CourseCover title="Docker" />)).toContain(">DO<");
+});
+
+test("SegmentedToggle marks the active option", () => {
+  const html = renderToString(<SegmentedToggle label="Look" value="b" onChange={() => {}} options={[{ value: "a", label: "A" }, { value: "b", label: "B" }]} />);
+  expect(html).toMatch(/aria-pressed="true"[^>]*>B</);
+});