Implement complete recurring event deletion with EXDATE and RRULE UNTIL support

Frontend Changes:
- Add DeleteAction enum with DeleteThis, DeleteFollowing, DeleteSeries options
- Update EventContextMenu to show different delete options for recurring events
- Add exception_dates field to CalendarEvent struct
- Fix occurrence generation to respect EXDATE exclusions
- Add comprehensive RRULE parsing with UNTIL date support
- Fix UNTIL date parsing to handle backend format (YYYYMMDDTHHMMSSZ)
- Enhanced debugging for RRULE processing and occurrence generation

Backend Changes:
- Add exception_dates field to CalendarEvent struct with EXDATE parsing/generation
- Implement update_event method for CalDAV client
- Add fetch_event_by_href helper function
- Update DeleteEventRequest model with delete_action and occurrence_date fields
- Implement proper delete_this logic with EXDATE addition
- Implement delete_following logic with RRULE UNTIL modification
- Add comprehensive logging for delete operations

CalDAV Integration:
- Proper EXDATE generation in iCal format for excluded occurrences
- RRULE modification with UNTIL clause for partial series deletion
- Event updating via CalDAV PUT operations
- Full iCal RFC 5545 compliance for recurring event modifications

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

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

src/components/event_context_menu.rs

@@ -1,12 +1,21 @@
 use yew::prelude::*;
 use web_sys::MouseEvent;
+use crate::services::calendar_service::CalendarEvent;
+
+#[derive(Clone, PartialEq, Debug)]
+pub enum DeleteAction {
+    DeleteThis,
+    DeleteFollowing,
+    DeleteSeries,
+}
 
 #[derive(Properties, PartialEq)]
 pub struct EventContextMenuProps {
     pub is_open: bool,
     pub x: i32,
     pub y: i32,
-    pub on_delete: Callback<MouseEvent>,
+    pub event: Option<CalendarEvent>,
+    pub on_delete: Callback<DeleteAction>,
     pub on_close: Callback<()>,
 }
 
@@ -23,11 +32,16 @@ pub fn event_context_menu(props: &EventContextMenuProps) -> Html {
         props.x, props.y
     );
 
-    let on_delete_click = {
+    // Check if the event is recurring
+    let is_recurring = props.event.as_ref()
+        .map(|event| event.recurrence_rule.is_some())
+        .unwrap_or(false);
+
+    let create_delete_callback = |action: DeleteAction| {
         let on_delete = props.on_delete.clone();
         let on_close = props.on_close.clone();
-        Callback::from(move |e: MouseEvent| {
-            on_delete.emit(e);
+        Callback::from(move |_: MouseEvent| {
+            on_delete.emit(action.clone());
             on_close.emit(());
         })
     };
@@ -38,10 +52,33 @@ pub fn event_context_menu(props: &EventContextMenuProps) -> Html {
             class="context-menu" 
             style={style}
         >
-            <div class="context-menu-item context-menu-delete" onclick={on_delete_click}>
-                <span class="context-menu-icon">{"🗑️"}</span>
-                {"Delete Event"}
-            </div>
+            {
+                if is_recurring {
+                    html! {
+                        <>
+                            <div class="context-menu-item context-menu-delete" onclick={create_delete_callback(DeleteAction::DeleteThis)}>
+                                <span class="context-menu-icon">{"🗑️"}</span>
+                                {"Delete This Event"}
+                            </div>
+                            <div class="context-menu-item context-menu-delete" onclick={create_delete_callback(DeleteAction::DeleteFollowing)}>
+                                <span class="context-menu-icon">{"🗑️"}</span>
+                                {"Delete Following Events"}
+                            </div>
+                            <div class="context-menu-item context-menu-delete" onclick={create_delete_callback(DeleteAction::DeleteSeries)}>
+                                <span class="context-menu-icon">{"🗑️"}</span>
+                                {"Delete Entire Series"}
+                            </div>
+                        </>
+                    }
+                } else {
+                    html! {
+                        <div class="context-menu-item context-menu-delete" onclick={create_delete_callback(DeleteAction::DeleteThis)}>
+                            <span class="context-menu-icon">{"🗑️"}</span>
+                            {"Delete Event"}
+                        </div>
+                    }
+                }
+            }
         </div>
     }
 }