[RAPID-micro] 메신저 ESC 키로 닫기 기능 추가

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

frontend/components/messenger/MessengerModal.tsx

@@ -33,6 +33,14 @@ export function MessengerModal() {
     setUnreadCount(Number(count));
   }, [serverUnread, setUnreadCount]);
 
+  useEffect(() => {
+    const onKeyDown = (e: KeyboardEvent) => {
+      if (e.key === "Escape" && isOpen) closeMessenger();
+    };
+    document.addEventListener("keydown", onKeyDown);
+    return () => document.removeEventListener("keydown", onKeyDown);
+  }, [isOpen, closeMessenger]);
+
 
   const selectedRoom = rooms.find((r) => r.id === selectedRoomId) || null;
   const [newRoomOpen, setNewRoomOpen] = useState(false);