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>

scripts/smoke.mjs

@@ -39,7 +39,8 @@ try {
   for (let i = 0; i < 100 && !target; i++) {
     try {
       const list = await (await fetch(`http://127.0.0.1:${port}/json`)).json()
-      target = list.find((t) => t.type === 'page')
+      // Chrome may list an extension page first; take the tab we opened.
+      target = list.find((t) => t.type === 'page' && t.url === 'about:blank') ?? list.find((t) => t.type === 'page' && !t.url.startsWith('chrome-extension://'))
     } catch { await sleep(100) }
   }
   if (!target) finish(1, 'FAIL: could not connect to Chrome')