- Add GET /api/period-history route with pagination, cycle length
calculation, and prediction accuracy tracking
- Add PATCH/DELETE /api/period-logs/[id] routes for editing and
deleting period entries with ownership validation
- Add /period-history page with table view, edit/delete modals,
and pagination controls
- Include 61 new tests covering all functionality
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
