refactor: use fake timers for deterministic 100ms delay test

[Copilot]

Description

Replaced real timer-based timing assertion with vi.useFakeTimers() to eliminate CI flakiness. The test verifying 100ms cookie propagation delay was using Date.now() comparison, which is susceptible to scheduler jitter and system load variations.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Code refactoring
• Performance improvement
• Test updates

Related Issues

Relates to #398

Changes Made

• Replaced Date.now() timing assertions with vi.useFakeTimers() and vi.advanceTimersByTimeAsync(100)
• Switched from userEvent to fireEvent (userEvent's built-in delays conflict with fake timers)
• Wrapped state updates in act() for proper React state handling
• Added explicit assertion that redirect doesn't occur before timer expires

Before:

const startTime = Date.now();
await user.click(button);
await waitFor(() => expect(mockPush).toHaveBeenCalled(), { timeout: 300 });
const elapsed = Date.now() - startTime;
expect(elapsed).toBeGreaterThanOrEqual(90);

After:

vi.useFakeTimers();
fireEvent.click(button);
expect(mockPush).not.toHaveBeenCalled();  // Verify delay not elapsed
await vi.advanceTimersByTimeAsync(100);
expect(mockPush).toHaveBeenCalledWith('/dashboard');  // Now called

Version Bump

• Version automatically bumped by workflow (same-repo PRs)
• Version manually bumped using node scripts/bump-version.js (fork PRs)
• Version already up-to-date (no bump needed)

Testing

Test Environment

• Node version: 23.x
• npm version: 10.x
• OS: Ubuntu

Tests Performed

• Unit tests pass (npm run test)
• E2E tests pass (npm run test:e2e)
• Linting passes (npm run lint)
• Manual testing completed

Test Coverage

All 20 AcceptTermsForm tests pass. Full test suite: 522 tests passed.

Documentation

• Documentation updated (if needed)
• Code comments added for complex logic
• API documentation updated (if API changes)

Checklist

• My code follows the project's code style
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings or errors
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published

Screenshots (if applicable)

N/A - test infrastructure change only

Additional Notes

Timer cleanup is handled by existing afterEach hook in the test suite's "Timing and Race Conditions" describe block.

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For maintainers:

• PR title follows conventional commit format
• Version bump is correct
• All checks pass
• Documentation is complete
• Ready to merge

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[Copilot]

Pull request overview

This PR refactors a flaky timing test to use deterministic fake timers instead of real timer-based timing assertions. The test verifies that the AcceptTermsForm component waits exactly 100ms before redirecting to ensure cookie propagation completes. Previously, the test used Date.now() comparison which was susceptible to CI scheduler jitter and system load variations.

Changes:

• Replaced Date.now() timing assertions with vi.useFakeTimers() and vi.advanceTimersByTimeAsync(100)
• Switched from userEvent to fireEvent to avoid conflicts between userEvent's built-in delays and fake timers
• Added explicit assertion to verify redirect doesn't occur before timer expires

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