Refactor create_event_modal into modular components

- Split massive 27K line modal into focused components
- Created event_form module with 6 tab components:
  * BasicDetailsTab - main event info with recurrence options properly positioned
  * AdvancedTab - status, privacy, priority
  * PeopleTab - organizer and attendees
  * CategoriesTab - event categories
  * LocationTab - location information
  * RemindersTab - reminder settings
- Added shared types and data structures
- Created new CreateEventModalV2 using modular architecture
- Recurrence options now positioned directly after repeat/reminder pickers

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/components/mod.rs

@@ -6,6 +6,7 @@ pub mod context_menu;
 pub mod create_calendar_modal;
 pub mod create_event_modal;
 pub mod event_context_menu;
+pub mod event_form;
 pub mod event_modal;
 pub mod login;
 pub mod month_view;