feat: Module 11 becomes 13; diff-tracks fuzzer; align the two reference tracks

- Rename course/11-break-your-engine to 13-break-your-engine and update every
  link and mention; start-module explains that Module 13 has no tests to start.
- tools/diff-tracks.mjs (npm run diff:tracks): stages both references of a
  module, generates a seeded random SpellGrid level and script per seed, pipes
  it to the Rust and TypeScript CLIs and diffs their output; crashes on one or
  both sides fail. stagePlay takes a module number.
- register_assembled: the TypeScript track compared only the text of an
  existing Assembled card, so a base re-registered with a new cost (or a
  different split) silently rewrote the earlier card. It now compares every
  field the engine reads, as Rust does (Modules 5-10).
  New test_05_assemble_never_rewrites_an_earlier_card.
- SpellGrid CLIs: coordinates and chooser numbers are 1-9 plain digits in both
  tracks (Rust accepted signs, TypeScript accepted "+2", "0x2", "1e0"); Rust
  quotes card names verbatim instead of with Debug escapes; Rust joins the
  minion list with "; " instead of rewriting ", ". Two new CLI tests per track.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

course/06-parser/reference/ts/src/engine/assemble.ts

@@ -34,6 +34,12 @@ const canonical = (value: unknown): string =>
       : v,
   );
 const sameText = (a: CardDef["text"], b: CardDef["text"]): boolean => canonical(a) === canonical(b);
+/** Two definitions the engine can't tell apart (it ignores `fictional` and `game`). */
+const sameCard = (a: CardDef, b: CardDef): boolean => {
+  const read = (d: CardDef) =>
+    canonical([d.name, d.type, d.cost, d.attack ?? 0, d.health ?? 0, d.noun ?? null, d.text, d.split]);
+  return read(a) === read(b);
+};
 
 /**
  * The base card with `half` of its text replaced by the same half of `donor`.
@@ -66,8 +72,8 @@ const changes = (base: CardDef, donor: CardDef, half: Half): boolean => {
 export function registerAssembled(world: World, def: CardDef): string {
   const stem = def.name.replace(/\)$/, "");
   let name = def.name;
-  // Same base, so the same name and stats: only the text can differ.
-  for (let n = 2; world.hasCard(name) && !sameText(world.card(name).def.text, def.text); n++) {
+  // A different card is any difference the engine reads: the text, the split, or a base re-registered since.
+  for (let n = 2; world.hasCard(name) && !sameCard(world.card(name).def, { ...def, name }); n++) {
     name = `${stem} ${n})`;
   }
   world.registerAssembled({ ...def, name });