fix: check write permission on explicit namespace in Add()

src/service/node_service_impl.go

@@ -499,6 +499,9 @@ func (s *nodeServiceImpl) Add(input AddInput) (*models.Node, error) {
 			if err != nil {
 				return err
 			}
+			if input.Namespace != "" && !pc.canWrite(nsID) {
+				return fmt.Errorf("permission denied: no write access to namespace %q", input.Namespace)
+			}
 			ownerID = nsID
 		}
 		if err := st.AddRel(ownerID, string(models.RelHasOwnership), id); err != nil {