Add calendar selection dropdown and fix multi-calendar event display

- Add calendar selection dropdown to event creation modal
- Update EventCreationData to include selected_calendar field
- Pass available calendars from user info to modal component
- Initialize dropdown with first available calendar as default
- Fix backend to fetch events from ALL calendars, not just the first
- Update refresh_event to search across all calendars
- Events created in any calendar now properly display in UI

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

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

src/components/create_event_modal.rs

@@ -1,6 +1,7 @@
 use yew::prelude::*;
 use web_sys::{HtmlInputElement, HtmlTextAreaElement, HtmlSelectElement};
 use chrono::{NaiveDate, NaiveTime};
+use crate::services::calendar_service::CalendarInfo;
 
 #[derive(Properties, PartialEq)]
 pub struct CreateEventModalProps {
@@ -8,6 +9,7 @@ pub struct CreateEventModalProps {
     pub selected_date: Option<NaiveDate>,
     pub on_close: Callback<()>,
     pub on_create: Callback<EventCreationData>,
+    pub available_calendars: Vec<CalendarInfo>,
 }
 
 #[derive(Clone, PartialEq, Debug)]
@@ -88,6 +90,7 @@ pub struct EventCreationData {
     pub reminder: ReminderType,
     pub recurrence: RecurrenceType,
     pub recurrence_days: Vec<bool>, // [Sun, Mon, Tue, Wed, Thu, Fri, Sat] for weekly recurrence
+    pub selected_calendar: Option<String>, // Calendar path
 }
 
 impl Default for EventCreationData {
@@ -114,6 +117,7 @@ impl Default for EventCreationData {
             reminder: ReminderType::default(),
             recurrence: RecurrenceType::default(),
             recurrence_days: vec![false; 7], // [Sun, Mon, Tue, Wed, Thu, Fri, Sat] - all false by default
+            selected_calendar: None,
         }
     }
 }
@@ -123,18 +127,25 @@ pub fn create_event_modal(props: &CreateEventModalProps) -> Html {
     let event_data = use_state(|| EventCreationData::default());
     
     // Initialize with selected date if provided
-    use_effect_with((props.selected_date, props.is_open), {
+    use_effect_with((props.selected_date, props.is_open, props.available_calendars.clone()), {
         let event_data = event_data.clone();
-        move |(selected_date, is_open)| {
+        move |(selected_date, is_open, available_calendars)| {
             if *is_open {
-                if let Some(date) = selected_date {
+                let mut data = if let Some(date) = selected_date {
                     let mut data = (*event_data).clone();
                     data.start_date = *date;
                     data.end_date = *date;
-                    event_data.set(data);
+                    data
                 } else {
-                    event_data.set(EventCreationData::default());
+                    EventCreationData::default()
+                };
+                
+                // Set default calendar to the first available one
+                if data.selected_calendar.is_none() && !available_calendars.is_empty() {
+                    data.selected_calendar = Some(available_calendars[0].path.clone());
                 }
+                
+                event_data.set(data);
             }
             || ()
         }
@@ -164,6 +175,18 @@ pub fn create_event_modal(props: &CreateEventModalProps) -> Html {
         })
     };
 
+    let on_calendar_change = {
+        let event_data = event_data.clone();
+        Callback::from(move |e: Event| {
+            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) };
+                event_data.set(data);
+            }
+        })
+    };
+
     let on_description_input = {
         let event_data = event_data.clone();
         Callback::from(move |e: InputEvent| {
@@ -420,6 +443,31 @@ pub fn create_event_modal(props: &CreateEventModalProps) -> Html {
                         />
                     </div>
 
+                    <div class="form-group">
+                        <label for="event-calendar">{"Calendar"}</label>
+                        <select 
+                            id="event-calendar"
+                            class="form-input" 
+                            onchange={on_calendar_change}
+                        >
+                            <option value="" selected={data.selected_calendar.is_none()}>{"Select calendar..."}</option>
+                            {
+                                props.available_calendars.iter().map(|calendar| {
+                                    let is_selected = data.selected_calendar.as_ref() == Some(&calendar.path);
+                                    html! {
+                                        <option 
+                                            key={calendar.path.clone()} 
+                                            value={calendar.path.clone()}
+                                            selected={is_selected}
+                                        >
+                                            {&calendar.display_name}
+                                        </option>
+                                    }
+                                }).collect::<Html>()
+                            }
+                        </select>
+                    </div>
+
                     <div class="form-group">
                         <label for="event-description">{"Description"}</label>
                         <textarea