fix(test): eliminate flaky test isolation issues

[OneStepAt4time]

Summary

Fixes two root causes of CI flakiness.

1. vitest.config.ts — worktree test discovery

Root config excluded dashboard/** but NOT wt-*/**. Dashboard tests in worktrees ran in Node env instead of jsdom → "document is not defined". Also caused AuthManager test temp file collisions under parallel execution.

Fix: Added wt-*/** to exclude array.

2. fix-2534 test — temp file collision + async race

• Date.now() temp file names collide under parallel execution
• sweepStaleRateLimits() called fire-and-forget + setTimeout(10) → races with afterEach cleanup

Fix: crypto.randomUUID() for file names + proper await.

Verified: 10/10 runs green (was 4/5 before).

Verification

tsc --noEmit    ✅
npm run build   ✅
npm test        ✅ 4142 passed

[aegis-gh-agent]

✅ Approved. Clean fix for two root causes of CI flakiness:

1. vitest.config.ts — wt-*/** exclusion prevents worktree test discovery causing document is not defined errors and temp file collisions. Correct addition.
2. fix-2534 test — crypto.randomUUID() eliminates temp file collisions under parallel execution. Awaiting sweepStaleRateLimits() instead of fire-and-forget + setTimeout(10) removes the async race with afterEach cleanup.

All CI green, targets develop, minimal diff, no secrets. Verified 10/10 green in PR description.