saveState method
Saves current workflow states to persistent storage.
Implementation
Future<void> saveState() async {
if (stateStore == null) return;
final statesData = <String, Map<String, dynamic>>{};
for (final entry in _states.entries) {
statesData[entry.key] = entry.value.toMap();
}
await stateStore!.save(_stateStoreKey, jsonEncode(statesData));
}