Complete frontend migration to shared VEvent model

- Update frontend to use shared calendar-models library
- Add display methods to VEvent for UI compatibility
- Remove duplicate VEvent definitions in frontend
- Fix JSON field name mismatch (dtstart/dtend vs start/end)
- Create CalendarEvent type alias for backward compatibility
- Resolve "missing field start" parsing error

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

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

frontend/src/services/calendar_service.rs

@@ -5,10 +5,11 @@ use wasm_bindgen_futures::JsFuture;
 use web_sys::{Request, RequestInit, RequestMode, Response};
 use std::collections::HashMap;
 
-// Import RFC 5545 compliant VEvent
-use crate::models::ical::VEvent;
+// Import RFC 5545 compliant VEvent from shared library
+use calendar_models::VEvent;
 
-// Create type alias for smooth transition
+// Create type alias for backward compatibility
+pub type CalendarEvent = VEvent;
 
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 pub struct EventReminder {
@@ -44,56 +45,7 @@ pub struct CalendarInfo {
     pub color: String,
 }
 
-#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
-pub struct CalendarEvent {
-    pub uid: String,
-    pub summary: Option<String>,
-    pub description: Option<String>,
-    pub start: DateTime<Utc>,
-    pub end: Option<DateTime<Utc>>,
-    pub location: Option<String>,
-    pub status: EventStatus,
-    pub class: EventClass,
-    pub priority: Option<u8>,
-    pub organizer: Option<String>,
-    pub attendees: Vec<String>,
-    pub categories: Vec<String>,
-    pub created: Option<DateTime<Utc>>,
-    pub last_modified: Option<DateTime<Utc>>,
-    pub recurrence_rule: Option<String>,
-    pub exception_dates: Vec<DateTime<Utc>>,
-    pub all_day: bool,
-    pub reminders: Vec<EventReminder>,
-    pub etag: Option<String>,
-    pub href: Option<String>,
-    pub calendar_path: Option<String>,
-}
-
-#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
-pub enum EventStatus {
-    Tentative,
-    Confirmed,
-    Cancelled,
-}
-
-impl Default for EventStatus {
-    fn default() -> Self {
-        EventStatus::Confirmed
-    }
-}
-
-#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
-pub enum EventClass {
-    Public,
-    Private,
-    Confidential,
-}
-
-impl Default for EventClass {
-    fn default() -> Self {
-        EventClass::Public
-    }
-}
+// CalendarEvent, EventStatus, and EventClass are now imported from shared library
 
 // ==================== V2 API MODELS ====================
 
@@ -228,15 +180,8 @@ impl CalendarService {
         year: i32, 
         month: u32
     ) -> Result<Vec<VEvent>, String> {
-        // Fetch CalendarEvents first
-        let calendar_events = self.fetch_events_for_month(token, password, year, month).await?;
-        
-        // Convert to VEvent
-        let vevents = calendar_events.into_iter()
-            .map(|event| VEvent::from_calendar_event(&event))
-            .collect();
-        
-        Ok(vevents)
+        // Since CalendarEvent is now a type alias for VEvent, just call the main method
+        self.fetch_events_for_month(token, password, year, month).await
     }
 
     pub async fn fetch_events_for_month(