- Fix master event detection in getEvent() to find VEVENT without recurrence-id
- Add removeOverrides parameter to updateSeries() to control override deletion
- Fetch master event when editing 'all events' to preserve original start date
- Combine master's date with form's time when updating all instances
- Detect time changes separately from date changes to preserve optimistic updates
- Only remove overrides when date/time/timezone/repeat rules change
- Keep overrides when only properties (title, description, etc) change
Fixes:
1. Old UI not cleared when editing all events
2. Start date not preserved when editing from different instance
3. Solo overrides incorrectly removed when only properties changed
4. Optimistic updates lost when editing recurring events
lenhanphung
af47923478