feat(client): listStores / addStore / removeStore for the store manager

Regenerate the gRPC stubs for the new HubAdmin store-management RPCs and
wrap them in HubClient (returns StoreSource list / Add+RemoveStoreResponse)
so Studio can list and edit the module-store list from the GUI.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/src/hub_client.dart

@@ -51,6 +51,9 @@ typedef VerifyEventChainResponse = pb.VerifyEventChainResponse;
 typedef CheckUpdateResponse = pb.CheckUpdateResponse;
 typedef ChannelStatusResponse = pb.ChannelStatusResponse;
 typedef ChannelEntry = pb.ChannelEntry;
+typedef StoreSource = pb.StoreSource;
+typedef AddStoreResponse = pb.AddStoreResponse;
+typedef RemoveStoreResponse = pb.RemoveStoreResponse;
 typedef SystemAiStatusResponse = pb.SystemAiStatusResponse;
 typedef AskAiResponse = pb.AskAiResponse;
 typedef ListSystemAiModelsResponse = pb.ListSystemAiModelsResponse;
@@ -646,6 +649,38 @@ class HubClient {
     return r.entries;
   }
 
+  /// List the configured module stores (operator config `stores:`) plus
+  /// the bundled seed, each with how many modules it contributes to the
+  /// live index. Backs the Studio store manager.
+  Future<List<StoreSource>> listStores() async {
+    final r = await _admin.listStores(pb.ListStoresRequest());
+    return r.stores;
+  }
+
+  /// Register a new module store. The hub fetches + validates its index,
+  /// persists it to config, and merges it live so its modules are
+  /// immediately searchable + installable.
+  Future<AddStoreResponse> addStore({
+    required String name,
+    required String url,
+    String bearerEnv = '',
+    String basicUser = '',
+    String basicPasswordEnv = '',
+  }) {
+    return _admin.addStore(pb.AddStoreRequest(
+      name: name,
+      url: url,
+      bearerEnv: bearerEnv,
+      basicUser: basicUser,
+      basicPasswordEnv: basicPasswordEnv,
+    ));
+  }
+
+  /// Drop a configured store by name. The bundled seed cannot be removed.
+  Future<RemoveStoreResponse> removeStore(String name) {
+    return _admin.removeStore(pb.RemoveStoreRequest(name: name));
+  }
+
   /// Install a module from a `.fai` bundle. [source] is either a
   /// URL or a local filesystem path; [expectedSha256] is an
   /// optional hex digest the hub verifies before unpacking.