Add color picker functionality to external calendars

- Enable clicking external calendar color icons to open color picker dropdown
- Implement backend API integration for updating external calendar colors
- Add conditional hover effects to prevent interference with color picker
- Use extremely high z-index (999999) to ensure dropdown appears above all elements
- Match existing CalDAV calendar color picker behavior and styling
- Support real-time color updates with immediate visual feedback
- Maintain color consistency across sidebar and calendar events

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

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

frontend/src/app.rs

@@ -567,8 +567,48 @@ pub fn App() -> Html {
 
     let on_color_change = {
         let user_info = user_info.clone();
+        let external_calendars = external_calendars.clone();
         let color_picker_open = color_picker_open.clone();
         Callback::from(move |(calendar_path, color): (String, String)| {
+            if calendar_path.starts_with("external_") {
+                // Handle external calendar color change
+                if let Ok(id_str) = calendar_path.strip_prefix("external_").unwrap_or("").parse::<i32>() {
+                    let external_calendars = external_calendars.clone();
+                    let color = color.clone();
+                    
+                    wasm_bindgen_futures::spawn_local(async move {
+                        // Find the external calendar to get its current details
+                        if let Some(cal) = (*external_calendars).iter().find(|c| c.id == id_str) {
+                            match CalendarService::update_external_calendar(
+                                id_str,
+                                &cal.name,
+                                &cal.url,
+                                &color,
+                                cal.is_visible,
+                            ).await {
+                                Ok(_) => {
+                                    // Update the local state
+                                    let mut updated_calendars = (*external_calendars).clone();
+                                    for calendar in &mut updated_calendars {
+                                        if calendar.id == id_str {
+                                            calendar.color = color.clone();
+                                            break;
+                                        }
+                                    }
+                                    external_calendars.set(updated_calendars);
+                                    
+                                    // No need to refresh events - they will automatically pick up the new color
+                                    // from the calendar when rendered since they use the same calendar_path matching
+                                }
+                                Err(e) => {
+                                    web_sys::console::error_1(&format!("Failed to update external calendar color: {}", e).into());
+                                }
+                            }
+                        }
+                    });
+                }
+            } else {
+                // Handle CalDAV calendar color change (existing logic)
                 if let Some(mut info) = (*user_info).clone() {
                     for calendar in &mut info.calendars {
                         if calendar.path == calendar_path {
@@ -582,6 +622,7 @@ pub fn App() -> Html {
                         let _ = LocalStorage::set("calendar_colors", json);
                     }
                 }
+            }
             color_picker_open.set(None);
         })
     };

frontend/src/components/sidebar.rs

@@ -256,7 +256,11 @@ pub fn sidebar(props: &SidebarProps) -> Html {
                                         html! {
                                             <li class="external-calendar-item" style="position: relative;">
                                                 <div 
-                                                    class="external-calendar-info"
+                                                    class={if props.color_picker_open.as_ref() == Some(&format!("external_{}", cal.id)) { 
+                                                        "external-calendar-info color-picker-active" 
+                                                    } else { 
+                                                        "external-calendar-info" 
+                                                    }}
                                                     oncontextmenu={{
                                                         let on_context_menu = on_external_calendar_context_menu.clone();
                                                         let cal_id = cal.id;
@@ -273,7 +277,48 @@ pub fn sidebar(props: &SidebarProps) -> Html {
                                                     <span 
                                                         class="external-calendar-color" 
                                                         style={format!("background-color: {}", cal.color)}
+                                                        onclick={{
+                                                            let on_color_picker_toggle = props.on_color_picker_toggle.clone();
+                                                            let external_id = format!("external_{}", cal.id);
+                                                            Callback::from(move |e: MouseEvent| {
+                                                                e.stop_propagation();
+                                                                on_color_picker_toggle.emit(external_id.clone());
+                                                            })
+                                                        }}
+                                                    >
+                                                        {
+                                                            if props.color_picker_open.as_ref() == Some(&format!("external_{}", cal.id)) {
+                                                                html! {
+                                                                    <div class="color-picker-dropdown">
+                                                                        {
+                                                                            props.available_colors.iter().map(|color| {
+                                                                                let color_str = color.clone();
+                                                                                let external_id = format!("external_{}", cal.id);
+                                                                                let on_color_change = props.on_color_change.clone();
+                                                                                
+                                                                                let on_color_select = Callback::from(move |_: MouseEvent| {
+                                                                                    on_color_change.emit((external_id.clone(), color_str.clone()));
+                                                                                });
+                                                                                
+                                                                                let is_selected = cal.color == *color;
+                                                                                
+                                                                                html! {
+                                                                                    <div
+                                                                                        key={color.clone()}
+                                                                                        class={if is_selected { "color-option selected" } else { "color-option" }}
+                                                                                        style={format!("background-color: {}", color)}
+                                                                                        onclick={on_color_select}
                                                                                     />
+                                                                                }
+                                                                            }).collect::<Html>()
+                                                                        }
+                                                                    </div>
+                                                                }
+                                                            } else {
+                                                                html! {}
+                                                            }
+                                                        }
+                                                    </span>
                                                     <span class="external-calendar-name">{&cal.name}</span>
                                                     <div class="external-calendar-actions">
                                                         {

frontend/styles.css

@@ -281,7 +281,7 @@ body {
     border-radius: 4px;
     padding: 1rem;
     box-shadow: 0 4px 12px rgba(0,0,0,0.15);
-    z-index: 1000;
+    z-index: 999999;
     display: grid;
     grid-template-columns: repeat(4, 1fr);
     gap: 0.75rem;
@@ -3677,7 +3677,7 @@ body {
     border: 1px solid var(--glass-bg);
 }
 
-.external-calendar-info:hover {
+.external-calendar-info:hover:not(.color-picker-active) {
     background: var(--glass-bg);
     border-color: var(--glass-bg-light);
     transform: translateX(2px);