Implement comprehensive event series editing via modal

## Frontend Changes:
- Add EditAction enum (EditThis, EditFuture, EditAll) to event context menu
- Update context menu to show 3 edit options for recurring events
- Enhance EventCreationData with edit_scope and changed_fields tracking
- Update app component to handle EditAction types and pass to modal
- Add field change tracking infrastructure to CreateEventModal

## Backend Changes:
- Add changed_fields parameter to UpdateEventSeriesRequest for optimization
- Existing series endpoint already supports the three update types:
  - "this_only" - creates exception with EXDATE
  - "this_and_future" - creates new series with UNTIL on original
  - "all_in_series" - updates existing series in-place

## Implementation Details:
- Event context menu shows single edit option for non-recurring events
- Recurring events get three options: "Edit This Event", "Edit This and Future Events", "Edit All Events in Series"
- Modal tracks which fields user actually changed for efficient updates
- Backend series endpoint already has the logic for all three update scenarios
- Full RFC 5545 compliance with proper EXDATE and UNTIL handling

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

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

frontend/src/components/create_event_modal.rs

@@ -4,6 +4,7 @@ use wasm_bindgen::JsCast;
 use chrono::{NaiveDate, NaiveTime, Local, TimeZone, Utc, Datelike};
 use crate::services::calendar_service::CalendarInfo;
 use crate::models::ical::VEvent;
+use crate::components::EditAction;
 
 #[derive(Properties, PartialEq)]
 pub struct CreateEventModalProps {
@@ -18,6 +19,8 @@ pub struct CreateEventModalProps {
     pub initial_start_time: Option<NaiveTime>,
     #[prop_or_default]
     pub initial_end_time: Option<NaiveTime>,
+    #[prop_or_default]
+    pub edit_scope: Option<EditAction>,
 }
 
 #[derive(Clone, PartialEq, Debug)]
@@ -330,6 +333,10 @@ pub struct EventCreationData {
     pub monthly_by_day: Option<String>, // For monthly: "1MO" = first Monday, "2TU" = second Tuesday, etc.
     pub monthly_by_monthday: Option<u8>, // For monthly: day of month (1-31)
     pub yearly_by_month: Vec<bool>, // For yearly: [Jan, Feb, Mar, ..., Dec]
+    
+    // Edit scope and tracking fields
+    pub edit_scope: Option<EditAction>,
+    pub changed_fields: Vec<String>, // List of field names that were changed
 }
 
 impl Default for EventCreationData {
@@ -365,6 +372,10 @@ impl Default for EventCreationData {
             monthly_by_day: None,
             monthly_by_monthday: None,
             yearly_by_month: vec![false; 12], // [Jan, Feb, ..., Dec] - all false by default
+            
+            // Edit scope and tracking defaults
+            edit_scope: None,
+            changed_fields: vec![],
         }
     }
 }
@@ -566,6 +577,10 @@ impl EventCreationData {
             } else {
                 vec![false; 12]
             },
+            
+            // Edit scope and tracking defaults (will be set later if needed)
+            edit_scope: None,
+            changed_fields: vec![],
         }
     }
 
@@ -593,9 +608,9 @@ pub fn create_event_modal(props: &CreateEventModalProps) -> Html {
     let active_tab = use_state(|| ModalTab::default());
     
     // Initialize with selected date or event data if provided
-    use_effect_with((props.selected_date, props.event_to_edit.clone(), props.is_open, props.available_calendars.clone(), props.initial_start_time, props.initial_end_time), {
+    use_effect_with((props.selected_date, props.event_to_edit.clone(), props.is_open, props.available_calendars.clone(), props.initial_start_time, props.initial_end_time, props.edit_scope.clone()), {
         let event_data = event_data.clone();
-        move |(selected_date, event_to_edit, is_open, available_calendars, initial_start_time, initial_end_time)| {
+        move |(selected_date, event_to_edit, is_open, available_calendars, initial_start_time, initial_end_time, edit_scope)| {
             if *is_open {
                 let mut data = if let Some(event) = event_to_edit {
                     // Pre-populate with event data for editing
@@ -625,6 +640,11 @@ pub fn create_event_modal(props: &CreateEventModalProps) -> Html {
                     data.selected_calendar = Some(available_calendars[0].path.clone());
                 }
                 
+                // Set edit scope if provided
+                if let Some(scope) = edit_scope {
+                    data.edit_scope = Some(scope.clone());
+                }
+                
                 event_data.set(data);
             }
             || ()
@@ -644,12 +664,25 @@ pub fn create_event_modal(props: &CreateEventModalProps) -> Html {
         })
     };
 
+    // Helper function to track field changes
+    let _track_field_change = |data: &mut EventCreationData, field_name: &str| {
+        if !data.changed_fields.contains(&field_name.to_string()) {
+            data.changed_fields.push(field_name.to_string());
+        }
+    };
+
     let on_title_input = {
         let event_data = event_data.clone();
         Callback::from(move |e: InputEvent| {
             if let Some(input) = e.target_dyn_into::<HtmlInputElement>() {
                 let mut data = (*event_data).clone();
-                data.title = input.value();
+                let new_value = input.value();
+                if data.title != new_value {
+                    data.title = new_value;
+                    if !data.changed_fields.contains(&"title".to_string()) {
+                        data.changed_fields.push("title".to_string());
+                    }
+                }
                 event_data.set(data);
             }
         })
@@ -661,7 +694,13 @@ pub fn create_event_modal(props: &CreateEventModalProps) -> Html {
             if let Some(select) = e.target_dyn_into::<HtmlSelectElement>() {
                 let mut data = (*event_data).clone();
                 let value = select.value();
-                data.selected_calendar = if value.is_empty() { None } else { Some(value) };
+                let new_calendar = if value.is_empty() { None } else { Some(value) };
+                if data.selected_calendar != new_calendar {
+                    data.selected_calendar = new_calendar;
+                    if !data.changed_fields.contains(&"selected_calendar".to_string()) {
+                        data.changed_fields.push("selected_calendar".to_string());
+                    }
+                }
                 event_data.set(data);
             }
         })