fix(ios): запуск на iOS — MapKit, ключ из xcconfig, CocoaPods

- AppDelegate: YMKMapKit до super, регистрация плагинов по шаблону Flutter 3.41
- Info.plist: YandexMapKitApiKey из $(YANDEX_MAPKIT_API_KEY)
- Debug/Release/Profile.xcconfig: ключ, include Pods и опциональный Secrets
- Podfile, workspace, pbxproj; .gitignore для Secrets.xcconfig, пример Secrets
- ios/README.md

Co-authored-by: Cursor <cursoragent@cursor.com>

ios/Runner/AppDelegate.swift

@@ -1,13 +1,29 @@
 import Flutter
 import UIKit
+import YandexMapsMobile
 
 @main
-@objc class AppDelegate: FlutterAppDelegate {
+@objc class AppDelegate: FlutterAppDelegate, FlutterImplicitEngineDelegate {
   override func application(
     _ application: UIApplication,
     didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
   ) -> Bool {
-    GeneratedPluginRegistrant.register(with: self)
+    let apiKey =
+      (Bundle.main.object(forInfoDictionaryKey: "YandexMapKitApiKey") as? String ?? "")
+      .trimmingCharacters(in: .whitespacesAndNewlines)
+    #if DEBUG
+    if apiKey.isEmpty || apiKey.contains("$(") {
+      assertionFailure(
+        "YandexMapKitApiKey пустой или не подставился из xcconfig — проверь YANDEX_MAPKIT_API_KEY в ios/Flutter/*.xcconfig"
+      )
+    }
+    #endif
+    YMKMapKit.setLocale(Locale.current.identifier)
+    YMKMapKit.setApiKey(apiKey)
     return super.application(application, didFinishLaunchingWithOptions: launchOptions)
   }
+
+  func didInitializeImplicitFlutterEngine(_ engineBridge: FlutterImplicitEngineBridge) {
+    GeneratedPluginRegistrant.register(with: engineBridge.pluginRegistry)
+  }
 }