Declare the Flutter scene delegate so the app launches on the iOS 27 SDK

[jasikpark]

Built with Xcode 27.0 (27A266a), the Runner app dies on launch with SIGTRAP before drawing anything:

Application failed to launch: UIScene life cycle is required for apps built with this SDK.
(UIApplication_RuntimeIssues.m:106)

Builds from the iOS 26 SDK are unaffected, so today's App Store build is fine. The crash arrives with whichever release is first built on Xcode 27.

Cause

ios/Runner/Info.plist declares a UIApplicationSceneManifest, but its UISceneConfigurations is an empty dict, so no scene delegate is ever named. AppDelegate already adopts FlutterImplicitEngineDelegate, so the AppDelegate half of the Flutter UIScene migration is done and only the plist half is missing. The iOS 26 SDK tolerated the empty configuration, the iOS 27 SDK treats it as not adopting the scene life cycle.

Fix

Name Flutter's scene delegate for the application role:

<key>UISceneConfigurations</key>
<dict>
  <key>UIWindowSceneSessionRoleApplication</key>
  <array>
    <dict>
      <key>UISceneClassName</key>
      <string>UIWindowScene</string>
      <key>UISceneConfigurationName</key>
      <string>flutter</string>
      <key>UISceneDelegateClassName</key>
      <string>FlutterSceneDelegate</string>
      <key>UISceneStoryboardFile</key>
      <string>Main</string>
    </dict>
  </array>
</dict>

Verified on an iPhone 13 Pro: a Profile build from Xcode 27.0 (27A266a) crashed at launch without this change and launches with it.

Xcode 27 also rejects the 14.0 deployment target. Raising it is a support decision, so it's in a separate PR stacked on this one.

🤖 Generated with Claude Code

https://claude.ai/code/session_01MurGUoeWWCURHtoWFB7R56