fix(desktop): focus the native window when a notification is clicked

On cinny-desktop (Tauri/WebView2) a clicked notification navigated the web
content but never raised the OS window (a service-worker/WebView2 client.focus()
only focuses the document). The service-worker notificationClick path now calls
a new focus_main_window Tauri command via invokeTauri (no-op outside Tauri) in
addition to navigating; the rich-toast path is focused natively on the Rust side.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/pages/client/ClientNonUIFeatures.tsx

@@ -55,6 +55,7 @@ import { toastQueueAtom } from '../../state/toast';
 import { useReminders } from '../../hooks/useReminders';
 import { getRoomRetentionMs, isExpired } from '../../utils/retention';
 import { useTauriUpdater } from '../../hooks/useTauriUpdater';
+import { invokeTauri } from '../../hooks/useTauri';
 import { TauriDesktopFeatures } from '../../components/TauriDesktopFeatures';
 import { KeyboardShortcutsDialog, useKeyboardShortcutsTrigger } from '../../features/shortcuts';
 import { useRoomsListener } from '../../hooks/useRoomsListener';
@@ -485,6 +486,10 @@ function MessageNotifications() {
     const onMessage = (event: MessageEvent) => {
       const data = event.data ?? {};
       if (data.type === 'notificationClick' && typeof data.path === 'string') {
+        // On desktop, raise the native window — a service-worker/WebView2
+        // `client.focus()` only focuses the document, not the OS window. No-op
+        // outside Tauri.
+        invokeTauri('focus_main_window');
         navigate(data.path);
       }
     };