feat: MCP-client federation surface (v0.12.0)

Picks up the four new HubAdmin RPCs that drive Studio's
MCP-clients editor:

- `listMcpClients()` — config + last-discovery snapshot.
- `refreshMcpClients()` — re-run discovery against the live
  daemon.
- `addMcpClient(name, endpoint, apiKeyEnv?, description?)` —
  persist + refresh in one round-trip.
- `removeMcpClient(name)` — drop persisted entry and live
  synthetic capabilities.

Typedefs for `ListMcpClientsResponse`, `McpClientStatus`,
`McpClientConfigEntry` so callers don't import generated/.

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

lib/src/hub_client.dart

@@ -57,6 +57,9 @@ typedef ClearEventLogResponse = pb.ClearEventLogResponse;
 typedef DaemonPathsResponse = pb.DaemonPathsResponse;
 typedef UninstallModuleResponse = pb.UninstallModuleResponse;
 typedef FetchModuleDocsResponse = pb.FetchModuleDocsResponse;
+typedef ListMcpClientsResponse = pb.ListMcpClientsResponse;
+typedef McpClientStatus = pb.McpClientStatus;
+typedef McpClientConfigEntry = pb.McpClientConfigEntry;
 typedef ModuleInfoResponse = pb.ModuleInfoResponse;
 typedef FlowSummary = pb.FlowSummary;
 typedef StoreEntry = pb.StoreEntry;
@@ -236,6 +239,40 @@ class HubClient {
     return _admin.fetchModuleDocs(pb.FetchModuleDocsRequest(name: name));
   }
 
+  /// List every configured MCP server with the last-discovery
+  /// snapshot. Drives Studio's MCP-clients editor.
+  Future<ListMcpClientsResponse> listMcpClients() {
+    return _admin.listMcpClients(Empty());
+  }
+
+  /// Re-run discovery against every configured MCP server and
+  /// update the running daemon's store-index in place.
+  Future<ListMcpClientsResponse> refreshMcpClients() {
+    return _admin.refreshMcpClients(Empty());
+  }
+
+  /// Persist a new MCP server in `~/.fai/config.yaml` and
+  /// trigger discovery in one round-trip.
+  Future<ListMcpClientsResponse> addMcpClient({
+    required String name,
+    required String endpoint,
+    String apiKeyEnv = '',
+    String description = '',
+  }) {
+    return _admin.addMcpClient(pb.McpClientConfigEntry(
+      name: name,
+      endpoint: endpoint,
+      apiKeyEnv: apiKeyEnv,
+      description: description,
+    ));
+  }
+
+  /// Remove an MCP server by name + drop its synthetic
+  /// capabilities from the running store-index.
+  Future<ListMcpClientsResponse> removeMcpClient(String name) {
+    return _admin.removeMcpClient(pb.RemoveMcpClientRequest(name: name));
+  }
+
   /// Read-only system-AI status. `enabled=false` lets Studio
   /// render "configure in Settings" without making a request.
   Future<SystemAiStatusResponse> systemAiStatus() {