chore: keep the fixture generator scripts and the replay-sample bot

scripts/fixtures/ holds the scripts that produced the 2026-11-11
fixtures, with a README on running them safely into a copy. Run in
order they reproduce the content of every fixture they touch.

Co-Authored-By: Claude Fable 5.2 <noreply@anthropic.com>

scripts/fixtures/m12-violations.mjs

@@ -0,0 +1,33 @@
+import { writeFileSync } from 'node:fs'
+// Fixture regeneration aid (see scripts/fixtures/README.md). Written during the 2026-11-11 build, kept for reference.
+// Writes into fixtures/ unless FIXTURES_OUT names another directory (with a trailing slash).
+const FIX = process.env.FIXTURES_OUT ?? new URL('../../fixtures/', import.meta.url).pathname
+const SOL = new URL('../../js/solutions/', import.meta.url).href
+const HERE = new URL('./', import.meta.url).pathname
+const { violations } = await import(SOL + 'check.js')
+const base = { width: 5, height: 5, snake: [{ x: 2, y: 2 }, { x: 1, y: 2 }, { x: 0, y: 2 }], dir: 'Right', nextDir: 'Right',
+  apple: { x: 4, y: 4 }, seed: 0, score: 0, status: 'Playing', frame: 0 }
+const P = (x, y) => ({ x, y })
+const cases = [
+  ['a-sane-state-has-no-violations', {}],
+  ['no-apple-is-fine', { apple: null }],
+  ['a-pending-perpendicular-turn-is-fine', { nextDir: 'Up' }],
+  ['a-one-cell-snake-is-fine', { snake: [P(0, 0)] }],
+  ['a-game-over-state-can-be-sane', { status: 'GameOver', snake: [P(4, 2), P(3, 2), P(2, 2)] }],
+  ['empty-snake', { snake: [] }],
+  ['head-off-the-right-edge', { snake: [P(5, 2), P(4, 2), P(3, 2)] }],
+  ['tail-above-the-board', { snake: [P(1, 1), P(1, 0), P(1, -1)] }],
+  ['head-on-its-own-body', { snake: [P(2, 2), P(2, 3), P(1, 3), P(1, 2), P(2, 2)] }],
+  ['snake-with-a-gap', { snake: [P(3, 2), P(1, 2), P(0, 2)] }],
+  ['snake-with-a-diagonal-step', { snake: [P(2, 2), P(1, 1), P(0, 1)] }],
+  ['apple-outside-the-board', { apple: P(5, 0) }],
+  ['apple-on-the-head', { apple: P(2, 2) }],
+  ['apple-on-the-tail', { apple: P(0, 2) }],
+  ['pending-turn-straight-back', { nextDir: 'Left' }],
+  ['pending-turn-straight-back-vertical', { dir: 'Up', nextDir: 'Down' }],
+  ['several-violations-are-listed-in-order', { snake: [P(5, 2), P(3, 2), P(3, 2)], apple: P(3, 2), nextDir: 'Left' }],
+  ['doubled-cell-counts-as-overlap-and-as-disconnected', { snake: [P(2, 2), P(2, 2)] }],
+]
+const fx = { function: 'violations', cases: cases.map(([name, patch]) => { const s = { ...base, ...patch }; return { name, args: [s], expected: violations(s) } }) }
+writeFileSync(FIX + 'm12-violations.json', JSON.stringify(fx, null, 2) + '\n')
+fx.cases.forEach((c) => console.log(c.name, JSON.stringify(c.expected)))