topology: operator-driven move-agent via set_parent (#486)

hive-c0re/src/server.rs

@@ -185,6 +185,17 @@ async fn dispatch(req: &HostRequest, coord: Arc<Coordinator>) -> HostResponse {
                 actions::deny(&coord, *id, None).await?;
                 HostResponse::success()
             }
+            HostRequest::SetParent { child, new_parent } => {
+                tracing::info!(%child, ?new_parent, "set_parent");
+                crate::topology::set_parent(child, new_parent.as_deref())
+                    .map_err(anyhow::Error::msg)?;
+                // ContainerView.parent is read from topology.json — a
+                // change here means every container row potentially
+                // moves in the dashboard tree. Rescan + diff-emit so
+                // open viewers repaint without polling.
+                coord.rescan_containers_and_emit().await;
+                HostResponse::success()
+            }
         })
     }
     .await;