hive-c0re: wire hivectl --graceful to enqueue GracefulStop

hive-c0re/src/bin/hivectl.rs

@@ -116,13 +116,12 @@ enum Cmd {
     Stop {
         #[command(flatten)]
         scope: ScopeArgs,
-        /// Gracefully quiesce each agent (finish the current turn, drain
-        /// the inbox) before stopping, instead of a hard stop.
-        ///
-        /// NOTE: not yet effective — the per-agent quiesce is still being
-        /// implemented (see the graceful-agent-stop tracker), so today
-        /// this falls through to a hard stop. The flag is accepted now so
-        /// the wire/CLI shape is stable when the quiesce lands.
+        /// Gracefully quiesce each agent before stopping, instead of a
+        /// hard stop. Each agent is enqueued as a `GracefulStop` on the
+        /// rebuild queue: the harness is signalled, runs one
+        /// stop-checkpoint turn to flush durable `/state`, drains, then
+        /// the container is stopped (bounded by a 3-min timeout that
+        /// falls back to a hard stop). Applies to agents only.
         #[arg(long)]
         graceful: bool,
     },