fix(#1916): direct the agent to end its turn on graceful stop instead of a fenced-empty recv

hive-ag3nt/src/mcp.rs

@@ -84,10 +84,23 @@ impl From<hive_sh4re::Response> for SocketReply {
             hive_sh4re::Response::HostJournal { content } => Self::HostJournal(content),
             hive_sh4re::Response::Schedules { schedules } => Self::Schedules(schedules),
             hive_sh4re::Response::Containers { containers } => Self::Containers(containers),
-            // A graceful stop is pending — the inbox is fenced. If claude polls
-            // `recv` during its stop-checkpoint turn, present it as an empty
-            // inbox (the serve loop is the real handler of this signal).
-            hive_sh4re::Response::GracefulStop => Self::Messages(Vec::new()),
+            // A graceful stop is pending — the inbox is fenced. Returning an
+            // *empty* inbox here is ambiguous: claude's "park on recv" habit
+            // makes it long-poll again instead of ending the turn, so the
+            // stop-checkpoint turn never finishes and the drain wait times out
+            // into a hard stop. Return a single explicit directive instead, so
+            // every recv during the stop unmissably tells claude to flush + end.
+            hive_sh4re::Response::GracefulStop => Self::Messages(vec![hive_sh4re::DeliveredMessage {
+                from: "graceful-stop".into(),
+                body: "⛔ GRACEFUL STOP IN PROGRESS — the container shuts down as soon as this turn \
+                       ends. Flush anything worth keeping to your durable /state files, then END \
+                       YOUR TURN now. Do NOT call recv again: the inbox is fenced and recv will \
+                       only keep returning this same notice."
+                    .into(),
+                id: 0,
+                redelivered: false,
+                in_reply_to: None,
+            }]),
             hive_sh4re::Response::AgentMeta {
                 name,
                 running,