feat(course): audit fixes and twelve extensions (Modules 7b, 12, 13)

Audit pass:
- Frame rule counts frames since the last move, so every step lasts
  exactly movesEvery(score) frames, also right after a speed-up
- clampTime + MAX_GAP_MS: a hidden tab no longer replays the whole gap
- Pong Restart keeps held keys
- Fact corrections (mulberry32 output coverage, Haskell IO, uniform)
- New fixture cases from a mutation analysis

Extensions (all three tracks, shared fixtures, course text):
- Turn queue (Exercise 10.6), persisted high score (10.7),
  replay viewer (10.8), play() end-to-end helper (9.5)
- Optional State (4.7) and optional Module 7b, stack-safe IO
- Module 12, property-based testing with generators, shrinking,
  invariants and a model-based oracle
- Module 13, Conway's Life with a Click event
- JS type checking via jsconfig, JSDoc and types.d.ts
- Maintainer tools: scripts/mutate.mjs, scripts/typecheck-js.sh,
  Playwright end-to-end suite (e2e/, scripts/e2e.sh)

Docs: docs/contract.md is the canonical contract; specs and build log
under docs/superpowers.

Verified: JS 728, Scala 689, F# 691 unit tests; stubs and progression
M01-M13 and M07b; 176 end-to-end tests on Chromium and WebKit.

Co-Authored-By: Claude Fable 5.2 <noreply@anthropic.com>

fsharp/build-web.sh

@@ -1,7 +1,8 @@
 #!/usr/bin/env bash
 # Usage: ./build-web.sh
 # Compiles src/ + web/ to JavaScript with Fable (a local dotnet tool, see .config/dotnet-tools.json) into web/dist/.
-# index.html loads the Snake entry module, pong.html the Pong one.
+# index.html loads the Snake entry module (web/dist/SnakeMain.js), pong.html the Pong one (PongMain.js), replay.html the
+# replay viewer (ReplayMain.js, m10) and life.html Conway's Life (LifeMain.js, m13).
 # Then serve the repo root (node scripts/serve.mjs) and open http://localhost:8000/fsharp/index.html.
 set -euo pipefail
 cd "$(dirname "$0")"