test(web): stabilize week registry clock

[Uarmagan]

Summary

• Freeze the Week event registry test clock so its May 2026 past/future examples stay stable.
• Restore real time after each test.

Evidence

• GitHub Actions Test run 26301965222 failed in unit (web), job 77429129727, at packages/web/src/views/Week/interaction/registry/weekEventRegistry.test.tsx:411.
• Local reproduction on ac02269 failed the same test because the event ending 2026-05-22 was treated as past on 2026-05-23.

Verification

• bun test --cwd packages/web src/views/Week/interaction/registry/weekEventRegistry.test.tsx
• bun test:web
• bun type-check
• bun lint

[tyler-dane]

Closed in favor of #1812. Changing the system time is a smell that the app code / test logic is brittle