chore: bootstrap agent-ready docs, rules and Bun workspace

Adds the approved v1 design spec, UI mockups, AGENTS.md (with CLAUDE.md
and GEMINI.md pointers), architecture/decisions/todo/permissions docs,
agent permission files, and an empty Bun workspaces skeleton.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

package.json

@@ -0,0 +1,14 @@
+{
+  "name": "sttracker",
+  "private": true,
+  "type": "module",
+  "workspaces": ["apps/*", "packages/*", "plugins/*"],
+  "scripts": {
+    "test": "bun test",
+    "typecheck": "tsc --noEmit -p tsconfig.json"
+  },
+  "devDependencies": {
+    "@types/bun": "latest",
+    "typescript": "^5"
+  }
+}