Add extra field to model instance (#14203)

### What problem does this PR solve?

Now each model support region with different URL

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

---------

Signed-off-by: Jin Hai <haijin.chn@gmail.com>

internal/cli/client.go

@@ -250,6 +250,8 @@ func (c *RAGFlowClient) ExecuteUserCommand(cmd *Command) (ResponseIf, error) {
 		return c.ShowCurrentModel(cmd)
 	case "set_default_model":
 		return c.SetDefaultModel(cmd)
+	case "reset_default_model":
+		return c.ResetDefaultModel(cmd)
 	case "list_user_default_models":
 		return c.ListDefaultModels(cmd)
 	// Dataset, metadata commands