fix(#1218): bulk topology move uses one git commit via new set-parent-bulk endpoint

hive-c0re/src/dashboard.rs

@@ -78,6 +78,7 @@ pub async fn serve(port: u16, coord: Arc<Coordinator>) -> Result<()> {
         .route("/retry-reminder/{id}", post(post_retry_reminder))
         .route("/request-spawn", post(post_request_spawn))
         .route("/api/topology/set-parent", post(post_set_parent))
+        .route("/api/topology/set-parent-bulk", post(post_set_parent_bulk))
         .route("/api/tool-groups", get(get_tool_groups))
         .route("/api/tool-groups/{agent}", post(post_tool_groups))
         .route("/api/capabilities", get(get_capabilities))
@@ -1054,6 +1055,15 @@ struct SetParentForm {
     new_parent: Option<String>,
 }
 
+/// One entry in a `POST /api/topology/set-parent-bulk` JSON array.
+/// `new_parent`: absent/null/empty-string all mean "promote to root".
+#[derive(Deserialize)]
+struct SetParentBulkEntry {
+    child: String,
+    #[serde(default)]
+    new_parent: Option<String>,
+}
+
 #[derive(Deserialize)]
 struct AnswerForm {
     answer: String,
@@ -2476,6 +2486,36 @@ async fn post_set_parent(
     }
 }
 
+/// `POST /api/topology/set-parent-bulk` — move multiple agents in a single
+/// request, producing **one** git commit. JSON body: `[{"child":"name",
+/// "new_parent":"target-or-null"}, ...]`. Empty array is a no-op (200 OK).
+/// First validation error aborts the whole batch.
+async fn post_set_parent_bulk(
+    State(state): State<AppState>,
+    axum::Json(body): axum::Json<Vec<SetParentBulkEntry>>,
+) -> Response {
+    if body.is_empty() {
+        return (StatusCode::OK, "ok").into_response();
+    }
+    // Collect borrows for the coordinator call.
+    let moves: Vec<(&str, Option<&str>)> = body
+        .iter()
+        .map(|e| {
+            let child: &str = &e.child;
+            let parent: Option<&str> = e.new_parent.as_deref().filter(|s| !s.is_empty());
+            (child, parent)
+        })
+        .collect();
+    match state.coord.reparent_bulk_with_notify(&moves).await {
+        Ok(()) => {
+            let names: Vec<&str> = body.iter().map(|e| e.child.as_str()).collect();
+            tracing::info!(agents = ?names, "operator: set-parent-bulk via dashboard");
+            (StatusCode::OK, "ok").into_response()
+        }
+        Err(e) => error_response(&format!("set-parent-bulk failed: {e}")),
+    }
+}
+
 // ── tool-group endpoints ──────────────────────────────────
 
 #[derive(Serialize)]