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.xcworkspace/contents.xcworkspacedata

@@ -4,4 +4,7 @@
    <FileRef
       location = "group:Runner.xcodeproj">
    </FileRef>
+   <FileRef
+      location = "group:Pods/Pods.xcodeproj">
+   </FileRef>
 </Workspace>