fix: 使用标准 FlutterAppDelegate 替代自定义类型

移除非标准的 FlutterImplicitEngineDelegate 和 FlutterImplicitEngineBridge
使用标准的 Flutter 插件注册方式

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: cw

opencli_mobile/ios/Runner/AppDelegate.swift

@@ -2,15 +2,12 @@ import Flutter
 import UIKit
 
 @main
-@objc class AppDelegate: FlutterAppDelegate, FlutterImplicitEngineDelegate {
+@objc class AppDelegate: FlutterAppDelegate {
   override func application(
     _ application: UIApplication,
     didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
   ) -> Bool {
+    GeneratedPluginRegistrant.register(with: self)
     return super.application(application, didFinishLaunchingWithOptions: launchOptions)
   }
-
-  func didInitializeImplicitFlutterEngine(_ engineBridge: FlutterImplicitEngineBridge) {
-    GeneratedPluginRegistrant.register(with: engineBridge.pluginRegistry)
-  }
 }