fix(ci): stabilize rolling dates in visual snapshots

Scope the Playwright fixed clock to visual cases while preserving shared browser seeding and running timers. Keep existing snapshots and tolerances unchanged.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: atulmgupta

web/e2e/harness.contract.spec.ts

@@ -44,6 +44,16 @@ test('browser globals are not monkeypatched by state seeding', () => {
   expect(source).not.toContain('HarnessEventSource');
 });
 
+test('visual date labels use a fixed clock without changing shared browser seeding', () => {
+  const visual = readFileSync(resolve(process.cwd(), 'e2e', 'visual.spec.ts'), 'utf8');
+  const seed = readFileSync(resolve(process.cwd(), 'e2e', 'mockApi.ts'), 'utf8');
+  const clock = "page.clock.setFixedTime(new Date('2026-09-13T12:00:00Z'))";
+  expect(visual).toContain(clock);
+  expect(visual.indexOf(clock)).toBeLessThan(visual.indexOf('page.goto'));
+  expect(seed).not.toContain('clock.setFixedTime');
+  expect(visual).not.toContain('clock.pauseAt');
+});
+
 test('Date semantics contract uses the standard hermetic API lifecycle', () => {
   const source = readFileSync(
     resolve(process.cwd(), 'e2e', 'date.contract.smoke.spec.ts'),

web/e2e/visual.spec.ts

@@ -93,6 +93,9 @@ for (const route of VISUAL_ROUTES) {
       : profile === 'large-fleet'
         ? 'large-fleet'
         : 'populated';
+    // Pin rolling date labels to the committed baseline day, without freezing timers.
+    // This clock is visual-only; the native Date contract uses the shared seed unchanged.
+    await page.clock.setFixedTime(new Date('2026-09-13T12:00:00Z'));
     await seedBrowserState(page, theme, route.path, { density });
     const mockApi = await installApiMocks(page, scenario, theme, density);
     await page.goto(route.path, { waitUntil: 'domcontentloaded' });