feat: Enable Firebase Cloud Messaging for iOS with platform-specific configurations and update Android build settings.

ios/Runner/AppDelegate.swift

@@ -1,5 +1,6 @@
 import Flutter
 import UIKit
+import FirebaseMessaging
 
 @main
 @objc class AppDelegate: FlutterAppDelegate {
@@ -10,4 +11,13 @@ import UIKit
     GeneratedPluginRegistrant.register(with: self)
     return super.application(application, didFinishLaunchingWithOptions: launchOptions)
   }
+
+  // Forward APNs token to Firebase for FCM
+  override func application(
+    _ application: UIApplication,
+    didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data
+  ) {
+    Messaging.messaging().apnsToken = deviceToken
+    super.application(application, didRegisterForRemoteNotificationsWithDeviceToken: deviceToken)
+  }
 }