hive-c0re/hivectl/hive-agent: pause as a job-queue DAG node (closes #3056)

hive-c0re/src/job_queue/power.rs

@@ -327,3 +327,31 @@ pub async fn stop_many(
     coord.emit_rebuild_queue_snapshot();
     Ok(ids)
 }
+
+/// Declare the pause DAG for `agents` — one `PauseSignal → PauseDrain`
+/// pair (see [`super::templates::pause_quiesce`]) per agent, independent
+/// roots on their own agent lease so a whole-hive pause overlaps rather
+/// than serialising.
+pub(crate) fn pause_nodes(builder: &JobBuilder, agents: &[String]) -> Vec<hive_jobq::NodeGuid> {
+    agents
+        .iter()
+        .map(|agent| super::templates::pause_quiesce(builder, agent).guid())
+        .collect()
+}
+
+/// Pause `agents` in a **single** DAG. Unlike `stop`/`start`/`restart`,
+/// this needs no live-state read first — `Coordinator::set_paused`
+/// works on a stopped container too (the marker is sticky), so there's
+/// no `running`/`stale` branch to resolve async before building.
+///
+/// # Errors
+/// Propagates a graph-insert error.
+pub async fn pause_many(
+    coord: &Arc<Coordinator>,
+    agents: &[String],
+) -> anyhow::Result<Vec<NodeId>> {
+    let targets: Vec<String> = agents.to_vec();
+    let ids = coord.job_queue.insert_job(|b| pause_nodes(b, &targets))?;
+    coord.emit_rebuild_queue_snapshot();
+    Ok(ids)
+}