- Record occurrence seen_ms from the observation time instead of flush time
- On session delete, only move first_seen when removed timestamps prove it was deleted; keep earlier dates from retention-pruned or legacy history
- Exact refresh fallback keeps subtraction-exact frequency and preserved first_seen
- Add tests for pruned history, legacy rows, and delayed flushes; update docs and change fragments
- Add a refresh key to OverviewTab that refetches overview, streak calendar, and known-words summary after single, day, or anime session deletes
- Reset loading/error state in useStreakCalendar on refetch
- Add OverviewTab tests covering each delete mode and a failed delete
- Document the automatic refresh and add changelog fragments
sudacode