CG-0MM0GQFZA1WQKILP: Add fixture transcript, generator script, and placeholder thumbnail

- Create scripts/generate-lc-fixture-transcript.ts: deterministic AI-vs-AI
  game runner using GreedyStrategy with fixed seeds (42/100/200)
- Generate tests/fixtures/transcripts/lost-cities/fixture-game.json:
  3-round match, 278 actions, deterministic and reproducible
- Add public/assets/games/lost-cities/thumbnail.png: 120x68 placeholder
  (solid dark teal, to be replaced by replay-generated screenshot)

Author: rgardler-msft

public/assets/games/lost-cities/thumbnail.png

@@ -0,0 +1,96 @@
+#!/usr/bin/env node
+/**
+ * Generate a deterministic fixture transcript for Lost Cities replay testing.
+ *
+ * Runs a full AI-vs-AI Lost Cities match (3 rounds) with fixed seeds
+ * and writes the resulting transcript JSON to
+ * tests/fixtures/transcripts/lost-cities/fixture-game.json.
+ *
+ * Usage:
+ *   npx tsx scripts/generate-lc-fixture-transcript.ts
+ */
+
+import {
+  setupLostCitiesGame,
+  executeAction,
+  getVisibleState,
+} from '../example-games/lost-cities/LostCitiesGame';
+import type { LostCitiesSession, PlayerId } from '../example-games/lost-cities/LostCitiesGame';
+import { LCTranscriptRecorder } from '../example-games/lost-cities/GameTranscript';
+import { LostCitiesAiPlayer, GreedyStrategy } from '../example-games/lost-cities/AiStrategy';
+import type { TurnPhase } from '../example-games/lost-cities/LostCitiesRules';
+import { writeFileSync, mkdirSync } from 'fs';
+import { dirname, resolve } from 'path';
+
+// Deterministic RNG (same LCG as tests)
+function createRng(seed: number): () => number {
+  let s = seed;
+  return () => {
+    s = (s * 1664525 + 1013904223) % 4294967296;
+    return s / 4294967296;
+  };
+}
+
+const session: LostCitiesSession = setupLostCitiesGame({
+  playerNames: ['Player 1', 'Player 2'],
+  isAI: [true, true],
+  rng: createRng(42),
+});
+
+const recorder = new LCTranscriptRecorder(session, ['greedy', 'greedy']);
+const ai0 = new LostCitiesAiPlayer(GreedyStrategy, createRng(100));
+const ai1 = new LostCitiesAiPlayer(GreedyStrategy, createRng(200));
+
+let actionCount = 0;
+const maxActions = 2000; // Safety limit (3 rounds × ~40 turns × 2 phases ≈ ~240 actions)
+
+while (session.matchPhase === 'playing' && actionCount < maxActions) {
+  const playerIndex: PlayerId = session.round.currentPlayer;
+  const phase: TurnPhase = session.round.turnPhase;
+  const ai = playerIndex === 0 ? ai0 : ai1;
+  const state = getVisibleState(session, playerIndex);
+
+  let action;
+  if (phase === 'PlayOrDiscard') {
+    action = ai.choosePhase1(state);
+  } else {
+    action = ai.choosePhase2(state);
+  }
+
+  const result = executeAction(session, action);
+  recorder.recordAction(session, result, action, phase);
+  actionCount++;
+
+  // Reset AI round history when a new round starts
+  if (result.roundEnded && !result.matchEnded) {
+    ai0.resetRoundHistory();
+    ai1.resetRoundHistory();
+  }
+}
+
+if (session.matchPhase !== 'match-over') {
+  console.error(`Match did not finish after ${maxActions} actions`);
+  process.exit(1);
+}
+
+const transcript = recorder.finalize(session);
+
+// Override timestamps for reproducibility
+transcript.metadata.startedAt = '2026-01-01T00:00:00.000Z';
+transcript.metadata.endedAt = '2026-01-01T00:15:00.000Z';
+
+const outPath = resolve('tests/fixtures/transcripts/lost-cities/fixture-game.json');
+mkdirSync(dirname(outPath), { recursive: true });
+writeFileSync(outPath, JSON.stringify(transcript, null, 2) + '\n');
+
+const totalActions = transcript.rounds.reduce(
+  (sum, r) => sum + r.actions.length,
+  0,
+);
+
+console.log(`Fixture transcript written to ${outPath}`);
+console.log(`  Rounds: ${transcript.rounds.length}`);
+console.log(`  Total actions: ${totalActions}`);
+console.log(
+  `  Winner: ${transcript.results!.winnerName} (${transcript.results!.finalScores.join('-')})`,
+);