feat: Implement Firebase push notifications with support for flavor-specific configurations.

ios/Runner/AppDelegate.swift

@@ -1,5 +1,7 @@
 import Flutter
 import UIKit
+import FirebaseCore
+import FirebaseMessaging
 
 @main
 @objc class AppDelegate: FlutterAppDelegate, FlutterImplicitEngineDelegate {
@@ -7,10 +9,39 @@ import UIKit
     _ application: UIApplication,
     didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
   ) -> Bool {
+    FirebaseApp.configure()
+
+    // Request notification permissions
+    UNUserNotificationCenter.current().delegate = self
+    let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
+    UNUserNotificationCenter.current().requestAuthorization(options: authOptions) { _, _ in }
+    application.registerForRemoteNotifications()
+
+    Messaging.messaging().delegate = self
+
     return super.application(application, didFinishLaunchingWithOptions: launchOptions)
   }
 
   func didInitializeImplicitFlutterEngine(_ engineBridge: FlutterImplicitEngineBridge) {
     GeneratedPluginRegistrant.register(with: engineBridge.pluginRegistry)
   }
+
+  override func application(
+    _ application: UIApplication,
+    didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data
+  ) {
+    Messaging.messaging().apnsToken = deviceToken
+    super.application(application, didRegisterForRemoteNotificationsWithDeviceToken: deviceToken)
+  }
+}
+
+extension AppDelegate: MessagingDelegate {
+  func messaging(_ messaging: Messaging, didReceiveRegistrationToken fcmToken: String?) {
+    let dataDict: [String: String] = ["token": fcmToken ?? ""]
+    NotificationCenter.default.post(
+      name: Notification.Name("FCMToken"),
+      object: nil,
+      userInfo: dataDict
+    )
+  }
 }