Migrate from FutureBuilder to a Riverpod AsyncNotifier in Flutter (flutter_riverpod 3.3.2)
A step-by-step migration from an inline FutureBuilder widget to a Riverpod AsyncNotifier in a real Flutter app: move the async work out of build, expose it as a provider, render with .when() or switch pattern matching, and add refresh and mutation methods. Tested on Flutter 3.44, Dart 3.x, flutter_riverpod 3.3.2.