saveSetup method
Implementation
Future<void> saveSetup(SavedPlaygroundSetup setup) async {
final idx = _savedSetups.indexWhere((s) => s.id == setup.id);
if (idx >= 0) {
_savedSetups[idx] = setup;
} else {
_savedSetups.add(setup);
}
await _storage.saveSetups(_savedSetups);
notifyListeners();
}