fix(web-e2e): expose serialize() on classic bridge; use real clock API

Two latent test bugs surfaced once the e2e suite actually ran (it had been
red on the webServer startup timeout, so these never executed): 14 passed,
4 failed.

- game.js `__FERROUS_DEBUG__` was missing `serialize()` — play.html's bridge
  has it but the /play-classic bridge (which the resume/move-history tests
  use) drifted. Added it (the wasm SolitaireGame already exposes serialize()).
- game_behaviors.spec.js called `page.clock.tick()`, which is the sinon name;
  Playwright's Clock API method is `page.clock.runFor()`. Replaced all 6 calls.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

solitaire_server/e2e/tests/game_behaviors.spec.js

@@ -136,7 +136,7 @@ test("new game button resets move history and score", async ({ page }) => {
 
 test("timer stops accumulating while tab is hidden", async ({ page }) => {
     // Install the fake clock before navigation so the game's setInterval is
-    // controlled by page.clock.tick() and won't fire on real wall-clock time.
+    // controlled by page.clock.runFor() and won't fire on real wall-clock time.
     await page.clock.install();
 
     await page.goto("/play-classic?seed=42");
@@ -144,7 +144,7 @@ test("timer stops accumulating while tab is hidden", async ({ page }) => {
     await waitForBridge(page);
 
     // Advance 3 fake seconds to get a non-zero timer reading.
-    await page.clock.tick(3_000);
+    await page.clock.runFor(3_000);
     const timerAfter3s = await page.locator("#hud-timer").textContent();
     expect(timerAfter3s).toBe("0:03");
 
@@ -152,7 +152,7 @@ test("timer stops accumulating while tab is hidden", async ({ page }) => {
     await setTabHidden(page, true);
 
     // Advance 10 fake seconds while hidden.
-    await page.clock.tick(10_000);
+    await page.clock.runFor(10_000);
     const timerWhileHidden = await page.locator("#hud-timer").textContent();
     expect(timerWhileHidden).toBe("0:03"); // must not have advanced
 
@@ -160,7 +160,7 @@ test("timer stops accumulating while tab is hidden", async ({ page }) => {
     await setTabHidden(page, false);
 
     // Advance 2 more fake seconds.
-    await page.clock.tick(2_000);
+    await page.clock.runFor(2_000);
     const timerAfterResume = await page.locator("#hud-timer").textContent();
     expect(timerAfterResume).toBe("0:05"); // only 3 + 2 visible seconds counted
 });
@@ -182,11 +182,11 @@ test("timer does not restart while tab is visible during an auto-complete or won
     // the snap state correctly gates the restart.
     //
     // Advance 2 s, then hide+show — timer should continue normally.
-    await page.clock.tick(2_000);
+    await page.clock.runFor(2_000);
     await setTabHidden(page, true);
-    await page.clock.tick(5_000);
+    await page.clock.runFor(5_000);
     await setTabHidden(page, false);
-    await page.clock.tick(2_000);
+    await page.clock.runFor(2_000);
 
     const timerText = await page.locator("#hud-timer").textContent();
     // 2 visible + 0 hidden + 2 visible = 4 total

solitaire_server/web/game.js

@@ -986,6 +986,9 @@ window.__FERROUS_DEBUG__ = {
     snapshot() {
         return game ? game.debug_snapshot() : null;
     },
+    serialize() {
+        return game ? game.serialize() : null;
+    },
     applyLegalMove(index) {
         if (!game) return { ok: false, error: "game_not_ready" };
         const result = game.debug_apply_legal_move(index);