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

hive-c0re/src/coordinator.rs

@@ -716,6 +716,57 @@ impl Coordinator {
         Ok(())
     }
 
+    /// Batch version of [`reparent_with_notify`]: applies all moves under a
+    /// single `META_LOCK` acquisition (one git commit) then sends per-agent
+    /// notifications for each move that actually changed topology.
+    /// First validation failure aborts the whole batch.
+    pub async fn reparent_bulk_with_notify(
+        self: &Arc<Self>,
+        moves: &[(&str, Option<&str>)],
+    ) -> std::result::Result<(), String> {
+        if moves.is_empty() {
+            return Ok(());
+        }
+        // bulk_commit_topology applies all set_parent calls under one lock
+        // and returns (child, old_parent) for every move that changed.
+        let changed = crate::meta::bulk_commit_topology(moves).await?;
+
+        // Send per-agent notifications for each changed move.
+        for (child, old_parent) in &changed {
+            // Find the new parent from the moves slice.
+            let new_parent = moves
+                .iter()
+                .find(|(c, _)| *c == child)
+                .and_then(|(_, np)| *np);
+            let old_label = old_parent.as_deref().unwrap_or("<root>");
+            let new_label = new_parent.unwrap_or("<root>");
+            if let Some(op) = old_parent.as_deref() {
+                let _ = self.broker.send(&hive_sh4re::Message {
+                    from: hive_sh4re::SYSTEM_SENDER.to_owned(),
+                    to: op.to_owned(),
+                    body: format!("{child} moved out of your subtree to {new_label}"),
+                    in_reply_to: None,
+                });
+            }
+            if let Some(np) = new_parent {
+                let _ = self.broker.send(&hive_sh4re::Message {
+                    from: hive_sh4re::SYSTEM_SENDER.to_owned(),
+                    to: np.to_owned(),
+                    body: format!(
+                        "{child} just moved into your subtree (was previously under {old_label})"
+                    ),
+                    in_reply_to: None,
+                });
+            }
+            let _ = self
+                .broker
+                .send_coalescing_reparent(child, old_label, new_label);
+        }
+
+        self.rescan_containers_and_emit().await;
+        Ok(())
+    }
+
     /// Read-only snapshot of the last cached container view. Used by
     /// `/api/state` to cold-load page-open clients without re-running
     /// `nixos-container list` themselves; the