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/life.html

@@ -0,0 +1,22 @@
+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <title>Pure Life</title>
+  <link rel="icon" href="data:,">
+  <style>
+    body { margin: 0; min-height: 100vh; display: flex; flex-direction: column; align-items: center;
+           justify-content: center; gap: 12px; background: #1b1b1b; color: #ddd; font: 14px system-ui, sans-serif; }
+    h1 { margin: 0; font-size: 20px; }
+    canvas { background: #111111; border: 2px solid #333; cursor: crosshair; }
+    p { margin: 0; color: #999; }
+  </style>
+</head>
+<body>
+  <h1>Pure Life</h1>
+  <canvas id="game" width="640" height="504"></canvas>
+  <p>Click a cell to switch it on or off. Space runs and pauses, N steps one generation, R fills the board at random, C clears it.</p>
+  <script type="module" src="web/dist/LifeMain.js"></script>
+</body>
+</html>