Version 2.0.0: Animation fixes, timing improvements, and E2E test suite

Animation fixes:
- Fix held card positioning bug (was appearing at bottom of page)
- Fix discard pile blank/white flash on turn transitions
- Fix blank card at round end by skipping animations during round_over/game_over
- Set card content before triggering flip animation to prevent flash
- Center suit symbol on 10 cards

Timing improvements:
- Reduce post-discard delay from 700ms to 500ms
- Reduce post-swap delay from 1800ms to 1000ms
- Speed up swap flip animation from 1150ms to 550ms
- Reduce CPU initial thinking delay from 150-250ms to 80-150ms
- Pause now happens after swap completes (showing result) instead of before

E2E test suite:
- Add Playwright-based test bot that plays full games
- State parser extracts game state from DOM for validation
- AI brain ports decision logic for automated play
- Freeze detector monitors for UI hangs
- Visual validator checks CSS states
- Full game, stress, and visual test specs

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/e2e/utils/timing.ts

@@ -0,0 +1,71 @@
+/**
+ * Animation timing constants from animation-queue.js
+ * Used to wait for animations to complete before asserting state
+ */
+export const TIMING = {
+  // Core animation durations (from CSS/animation-queue.js)
+  flipDuration: 540,
+  moveDuration: 270,
+  pauseAfterFlip: 144,
+  pauseAfterDiscard: 550,
+  pauseBeforeNewCard: 150,
+  pauseAfterSwapComplete: 400,
+  pauseBetweenAnimations: 90,
+
+  // Derived waits for test actions
+  get flipComplete() {
+    return this.flipDuration + this.pauseAfterFlip + 100;
+  },
+  get swapComplete() {
+    return this.flipDuration + this.pauseAfterFlip + this.moveDuration +
+           this.pauseAfterDiscard + this.pauseBeforeNewCard +
+           this.moveDuration + this.pauseAfterSwapComplete + 200;
+  },
+  get drawComplete() {
+    return this.moveDuration + this.pauseBeforeNewCard + 100;
+  },
+
+  // Safety margins for network/processing
+  networkBuffer: 200,
+  safetyMargin: 300,
+
+  // Longer waits
+  turnTransition: 500,
+  cpuThinkingMin: 400,
+  cpuThinkingMax: 1200,
+  roundOverDelay: 1000,
+};
+
+/**
+ * Wait for animation queue to drain
+ */
+export async function waitForAnimations(page: import('@playwright/test').Page, timeout = 5000): Promise<void> {
+  await page.waitForFunction(
+    () => {
+      const game = (window as any).game;
+      if (!game?.animationQueue) return true;
+      return !game.animationQueue.isAnimating();
+    },
+    { timeout }
+  );
+}
+
+/**
+ * Wait for WebSocket to be ready
+ */
+export async function waitForWebSocket(page: import('@playwright/test').Page, timeout = 5000): Promise<void> {
+  await page.waitForFunction(
+    () => {
+      const game = (window as any).game;
+      return game?.ws?.readyState === WebSocket.OPEN;
+    },
+    { timeout }
+  );
+}
+
+/**
+ * Wait a fixed time plus safety margin
+ */
+export function safeWait(duration: number): number {
+  return duration + TIMING.safetyMargin;
+}