fix: Tray-Icon API kompatibel (kein Image::from_bytes)

Nutzt default_window_icon() statt Image::from_bytes das in
dieser Tauri-Version nicht existiert.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

clients/desktop/src-tauri/src/lib.rs

@@ -555,9 +555,8 @@ pub fn run() {
             let sync_now = MenuItem::with_id(app, "sync", "Jetzt synchronisieren", true, None::<&str>)?;
             let menu = Menu::with_items(app, &[&show, &sync_now, &quit])?;
 
-            // Use bundled icon for tray
-            let icon = app.default_window_icon().cloned()
-                .unwrap_or_else(|| tauri::image::Image::from_bytes(include_bytes!("../icons/32x32.png")).unwrap());
+            // Use window icon for tray (set via tauri.conf.json)
+            let icon = app.default_window_icon().cloned();
 
             // Handle .cloud file opened via file association (double-click)
             let args: Vec<String> = std::env::args().collect();
@@ -574,8 +573,9 @@ pub fn run() {
                 }
             }
 
-            TrayIconBuilder::new()
-                .icon(icon)
+            let mut tray = TrayIconBuilder::new();
+            if let Some(ic) = icon { tray = tray.icon(ic); }
+            tray
                 .tooltip("Mini-Cloud Sync")
                 .menu(&menu)
                 .on_menu_event(|app, event| {