Agent Skills: flutter-riverpod-state-management

Implement reactive state management using Riverpod 2.0 with code generation in Flutter. Use when defining @riverpod providers, building AsyncNotifiers, overriding providers in tests, or enforcing immutable state with Freezed models. (triggers: **_provider.dart, **_notifier.dart, riverpod, ProviderScope, ConsumerWidget, Notifier, AsyncValue, ref.watch, @riverpod)