Implement complete event series endpoints with full CRUD support

## Backend Implementation
- Add dedicated series endpoints: create, update, delete
- Implement RFC 5545 compliant RRULE generation and modification
- Support all scope operations: this_only, this_and_future, all_in_series
- Add comprehensive series-specific request/response models
- Implement EXDATE and RRULE modification for precise occurrence control

## Frontend Integration
- Add automatic series detection and smart endpoint routing
- Implement scope-aware event operations with backward compatibility
- Enhance API payloads with series-specific fields
- Integrate existing RecurringEditModal for scope selection UI

## Testing
- Add comprehensive integration tests for all series endpoints
- Validate scope handling, RRULE generation, and error scenarios
- All 14 integration tests passing

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

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

frontend/src/app.rs

@@ -2,7 +2,7 @@ use yew::prelude::*;
 use yew_router::prelude::*;
 use gloo_storage::{LocalStorage, Storage};
 use web_sys::MouseEvent;
-use crate::components::{Sidebar, ViewMode, Theme, CreateCalendarModal, ContextMenu, EventContextMenu, CalendarContextMenu, CreateEventModal, EventCreationData, RouteHandler, EventStatus, EventClass, ReminderType, RecurrenceType, DeleteAction};
+use crate::components::{Sidebar, ViewMode, Theme, CreateCalendarModal, ContextMenu, EventContextMenu, CalendarContextMenu, CreateEventModal, EventCreationData, RouteHandler, EventStatus, EventClass, ReminderType, RecurrenceType, DeleteAction, RecurringEditModal, RecurringEditAction};
 use crate::services::{CalendarService, calendar_service::UserInfo};
 use crate::models::ical::VEvent;
 use chrono::NaiveDate;
@@ -54,6 +54,9 @@ pub fn App() -> Html {
     let calendar_context_menu_date = use_state(|| -> Option<NaiveDate> { None });
     let create_event_modal_open = use_state(|| false);
     let selected_date_for_event = use_state(|| -> Option<NaiveDate> { None });
+    let recurring_edit_modal_open = use_state(|| false);
+    let recurring_edit_event = use_state(|| -> Option<VEvent> { None });
+    let recurring_edit_data = use_state(|| -> Option<EventCreationData> { None });
     
     // Calendar view state - load from localStorage if available
     let current_view = use_state(|| {