feat(notifications): initialize Firebase Messaging and Capacitor push on native

Add firebaseMessagingClient to ensure the Firebase app is created from VITE_FIREBASE_*,
wire PushNotifications (listeners, requestPermissions, register) before token work,
and call getMessaging/getToken/onMessage when firebase/messaging is supported. Hook
startup from main.capacitor and set PushNotifications presentationOptions in
capacitor.config. Depend on firebase and @capacitor/push-notifications.

capacitor.config.ts

@@ -18,6 +18,9 @@ const config: CapacitorConfig = {
         ]
       }
     },
+    PushNotifications: {
+      presentationOptions: ['badge', 'sound', 'alert']
+    },
     SplashScreen: {
       launchShowDuration: 3000,
       launchAutoHide: true,