feat(useragent): bootstrap / unseal flow implementattion

useragent/lib/providers/vault_state.dart

@@ -0,0 +1,27 @@
+import 'package:arbiter/proto/user_agent.pb.dart';
+import 'package:arbiter/providers/connection/connection_manager.dart';
+import 'package:mtcore/markettakers.dart';
+import 'package:protobuf/well_known_types/google/protobuf/empty.pb.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+part 'vault_state.g.dart';
+
+@riverpod
+Future<VaultState?> vaultState(Ref ref) async {
+  final conn = await ref.watch(connectionManagerProvider.future);
+  if (conn == null) {
+    return null;
+  }
+
+  await conn.send(UserAgentRequest(queryVaultState: Empty()));
+
+  final resp = await conn.receive();
+  if (resp.whichPayload() != UserAgentResponse_Payload.vaultState) {
+    talker.warning('Expected vault state response, got ${resp.whichPayload()}');
+    return null;
+  }
+
+  final vaultState = resp.vaultState;
+
+  return vaultState;
+}