iOS: show transfer notifications as banners while the app is open

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

ios/Runner/AppDelegate.swift

@@ -1,5 +1,6 @@
 import Flutter
 import UIKit
+import UserNotifications
 
 @main
 @objc class AppDelegate: FlutterAppDelegate, FlutterImplicitEngineDelegate {
@@ -8,7 +9,20 @@ import UIKit
     didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
   ) -> Bool {
     TransferManager.shared.reconnect()
-    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
+    let launched = super.application(application, didFinishLaunchingWithOptions: launchOptions)
+    UNUserNotificationCenter.current().delegate = self
+    return launched
+  }
+
+  /// A transfer summary ("Downloaded 1 file") usually finishes while the app
+  /// is open; without this iOS delivers it silently to Notification Center
+  /// instead of showing the banner.
+  override func userNotificationCenter(
+    _ center: UNUserNotificationCenter,
+    willPresent notification: UNNotification,
+    withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void
+  ) {
+    completionHandler([.banner, .list, .sound])
   }
 
   override func application(