docs(#2591): fix stale Claim.agent doc + explain cancel's container roll-up (argus review)

hive-c0re/src/job_queue/mod.rs

@@ -71,7 +71,7 @@ pub struct Claim {
     pub node_id: NodeId,
     pub kind: NodeKind,
     /// The agent this node targets (its own, not a DAG-level field). Empty for
-    /// the internal [`NodeKind::Finalize`] node.
+    /// the agentless [`NodeKind::MetaLock`] + [`NodeKind::Dag`] container nodes.
     pub agent: String,
     pub template: Template,
     pub approval_id: Option<i64>,
@@ -452,8 +452,12 @@ impl JobQueue {
         for id in work {
             inner.sched.cancel_node(id);
         }
-        // Roll the container up so the DAG reaches a terminal state (all children
-        // now `Cancelled`); `dag_rollup` reports `Cancelled` to the wire.
+        // The container was settled to `Finishing` at submit; completing it again
+        // now re-runs the roll-up with its children all `Cancelled`, driving it to
+        // a terminal state synchronously within this lock — so the caller reads
+        // the terminal summary immediately instead of waiting for the scheduler
+        // loop to observe the cancellation. `dag_rollup` reports `Cancelled` to
+        // the wire (a container whose children all cancelled).
         inner.sched.complete(container, Outcome::Done);
         let terminal = inner.terminal_dag(container);
         drop(inner);