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/solutions/life/View.scala

@@ -0,0 +1,21 @@
+package snake
+package life
+
+import LifeModel.*
+
+/** m13 life view: live cells as squares, and a status strip under the board. */
+object LifeView:
+
+  private val W = LW * LCELL
+  private val H = LH * LCELL
+
+  private def text(x: Int, y: Int, str: String, align: String): Shape = Shape.Text(x, y, str, "#ffffff", 14, align)
+
+  def lifeView(state: LifeState): Scene =
+    Shape.Rect(0, 0, W, H, "#111111") ::
+      state.cells.map(p => Shape.Rect(p.x * LCELL + 1, p.y * LCELL + 1, LCELL - 2, LCELL - 2, "#7cb342")) ++
+      List(
+        Shape.Rect(0, H, W, STRIP, "#222222"),
+        text(6, H + 17, s"Generation ${state.generation}", "left"),
+        text(W - 6, H + 17, if state.running then "Running: Space pauses" else "Paused: Space runs, N steps", "right")
+      )