feat: Add push notification support with VAPID keys

- Backend: web-push integration with VAPID keys
- Push subscription endpoints (GET /api/push/public-key, POST /api/push/subscribe)
- In-memory subscription store
- Frontend: Auto-subscribe to push after notification permission granted
- Service Worker: Push event handler
- Send push notifications when torrents complete
- Works even when browser is closed

frontend/sw.js

@@ -98,20 +98,23 @@ self.addEventListener('notificationclick', (event) => {
     );
 });
 
-// Push notification event (for future use)
+// Push notification event
 self.addEventListener('push', (event) => {
-    console.log('[Service Worker] Push received');
+    console.log('[Service Worker] Push notification received');
     const data = event.data ? event.data.json() : {};
     
+    const title = data.title || 'VibeTorrent';
     const options = {
-        body: data.message || 'New notification',
-        icon: '/icon-192.png',
-        badge: '/icon-192.png',
+        body: data.body || 'New notification',
+        icon: data.icon || '/icon-192.png',
+        badge: data.badge || '/icon-192.png',
         tag: data.tag || 'vibetorrent-notification',
         requireInteraction: false,
     };
     
+    console.log('[Service Worker] Showing notification:', title, options);
+    
     event.waitUntil(
-        self.registration.showNotification(data.title || 'VibeTorrent', options)
+        self.registration.showNotification(title, options)
     );
 });