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>

scala/test/M09App.test.scala

@@ -28,12 +28,18 @@ class M09AppSuite extends munit.FunSuite:
     assertEquals(IO.trace(App.render(Spawn.newGame(42)), 0).ops, View.view(Spawn.newGame(42)).map(Op.Draw(_)))
   }
 
+  // Module 10 (Exercise 10.7) makes `main` also load the stored best and draw one more shape after the game's view,
+  // so this test accepts both versions; m10 pins the final one exactly.
   test("main asks for a random seed, then builds the stream from it") {
     val traced = IO.trace(App.main, 42)
-    assertEquals(traced.ops, List(Op.RandomSeed))
+    assert(
+      traced.ops == List(Op.RandomSeed) || traced.ops == List(Op.RandomSeed, Op.LoadBest),
+      s"main may only ask for the seed (and, from m10 on, the stored best); it asked for ${traced.ops}"
+    )
     val (outs, _) = traced.result.step(time(0))
     assertEquals(outs.length, 1)
-    assertEquals(drawn(outs.head), View.view(Spawn.newGame(42)))
+    val expected = View.view(Spawn.newGame(42))
+    assertEquals(drawn(outs.head).take(expected.length), expected)
   }
 
   // `main` itself switches to speedActions in m10, so the 150 ms behaviour is checked on the same program built from classicActions.
@@ -54,3 +60,21 @@ class M09AppSuite extends munit.FunSuite:
     assertEquals(first.length, 1)
     assert(later.nonEmpty)
   }
+
+  // ---- play: the whole program in one equality (Exercise 9.5)
+
+  private def drawOps(state: GameState): List[Op] = View.view(state).map(Op.Draw(_))
+
+  test("play on the classic program equals the scenes of the expected states") {
+    val events = List(time(150), down("ArrowUp"), down("x"), time(300), time(310))
+    val expectedStates = Game.history(Spawn.newGame(42), List(Action.Tick, Action.Turn(Direction.Up), Action.Tick))
+    assertEquals(App.play(classicMain, 42, events), expectedStates.map(drawOps))
+  }
+
+  test("play with no events gives no drawings") {
+    assertEquals(App.play(classicMain, 42, Nil), Nil)
+  }
+
+  test("play uses the seed for the program's RandomSeed") {
+    assertEquals(App.play(classicMain, 7, List(time(0))), List(drawOps(Spawn.newGame(7))))
+  }