job_queue: add NodeKind::Reparent (topology moves as a queue node, #2719)

hive-c0re/src/job_queue/submit.rs

@@ -420,3 +420,28 @@ pub fn meta_update(
 ) -> u64 {
     submit_and_emit(coord, templates::meta_update(inputs, source, reason, None))
 }
+
+/// Topology move(s) as a queue DAG. `moves` is `(child, new_parent)` pairs —
+/// one entry for `set-parent`, N for `set-parent-bulk`. Not yet wired to the
+/// `set-parent`/`set-parent-bulk` HTTP handlers or the `hivectl`/MCP
+/// `SetParent` surface — those still call `Coordinator::reparent*_with_notify`
+/// directly, which blocks until the commit lands and returns a synchronous
+/// `ok`/`err`, unlike every other queue-backed op. Whether that call-site
+/// swap should keep the synchronous contract or go fire-and-forget (submit
+/// returns a DAG id immediately, like everything else in this module) is an
+/// open question — exists so the `NodeKind::Reparent` shape is exercised
+/// end-to-end (tests, and any future caller) ahead of that call-site swap.
+#[allow(
+    dead_code,
+    reason = "landed ahead of the server.rs/dashboard::topology call-site swap, pending an \
+               answer on whether that swap should be synchronous or fire-and-forget — \
+               exercised today by job_queue::tests"
+)]
+pub fn reparent(
+    coord: &Arc<Coordinator>,
+    moves: Vec<(hive_types::Ident, Option<hive_types::Ident>)>,
+    source: Source,
+    reason: String,
+) -> u64 {
+    submit_and_emit(coord, templates::reparent(moves, source, reason))
+}