vgv-dart-flutter-sdk-upgrade

VGV-specific reference for bumping Dart and Flutter SDK constraints across packages. Use when upgrading the Flutter or Dart SDK version in any VGV repository — bumping pubspec.yaml environment constraints, updating CI workflow Flutter versions, or preparing an SDK upgrade PR. CI uses ^MAJOR.MINOR.x to resolve to the latest patch; pubspec pins the exact patch version (e.g., ^3.50.1). Trigger on phrases like "bump Flutter to 3.x", "update SDK constraints", "upgrade Dart SDK", "update CI Flutter version", "bump SDK version", or "prep the SDK upgrade PR".