Complete event modal migration: remove original and rename V2

Remove the original create_event_modal.rs and rename create_event_modal_v2.rs
to complete the modal migration started earlier. This eliminates duplicate code
and consolidates to a single, clean event modal implementation.

Changes:
- Remove original create_event_modal.rs (2,300+ lines)
- Rename create_event_modal_v2.rs → create_event_modal.rs
- Update component/function names: CreateEventModalV2 → CreateEventModal
- Fix all imports in app.rs and calendar.rs
- Add missing to_create_event_params() method to EventCreationData
- Resolve EditAction type conflicts between modules
- Clean up duplicate types and unused imports
- Maintain backwards compatibility with EventCreationData export

Result: -2440 lines, +160 lines - massive code cleanup with zero functionality loss.

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

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

frontend/src/components/mod.rs

@@ -5,7 +5,6 @@ pub mod calendar_list_item;
 pub mod context_menu;
 pub mod create_calendar_modal;
 pub mod create_event_modal;
-pub mod create_event_modal_v2;
 pub mod event_context_menu;
 pub mod event_form;
 pub mod event_modal;
@@ -22,10 +21,9 @@ pub use calendar_header::CalendarHeader;
 pub use calendar_list_item::CalendarListItem;
 pub use context_menu::ContextMenu;
 pub use create_calendar_modal::CreateCalendarModal;
-pub use create_event_modal::{
-    CreateEventModal, EventClass, EventCreationData, EventStatus, RecurrenceType, ReminderType,
-};
-pub use create_event_modal_v2::CreateEventModalV2;
+pub use create_event_modal::CreateEventModal;
+// Re-export event form types for backwards compatibility
+pub use event_form::EventCreationData;
 pub use event_form::{
     EventClass as EventFormClass, EventCreationData as EventFormData, EventStatus as EventFormStatus, 
     RecurrenceType as EventFormRecurrenceType, ReminderType as EventFormReminderType,