[RAPID-fix] 스크롤 근본 원인 수정: isOpen deps 추가로 메신저 열릴 때마다 하단 스크롤

frontend/components/messenger/ChatPanel.tsx

@@ -16,7 +16,7 @@ interface ChatPanelProps {
 
 export function ChatPanel({ room }: ChatPanelProps) {
   const { user } = useAuth();
-  const { selectedRoomId } = useMessengerContext();
+  const { selectedRoomId, isOpen } = useMessengerContext();
   const { data: messages } = useMessages(selectedRoomId);
   const markAsRead = useMarkAsRead();
   const updateRoom = useUpdateRoom();
@@ -38,14 +38,15 @@ export function ChatPanel({ room }: ChatPanelProps) {
 
   // Scroll to bottom: sentinel scrollIntoView before paint (no visible jump)
   useLayoutEffect(() => {
-    bottomRef.current?.scrollIntoView();
-  }, [selectedRoomId, lastMessageId]);
+    if (isOpen) bottomRef.current?.scrollIntoView();
+  }, [selectedRoomId, lastMessageId, isOpen]);
 
   // Second pass for async image loads
   useEffect(() => {
+    if (!isOpen) return;
     const t = setTimeout(() => { bottomRef.current?.scrollIntoView(); }, 600);
     return () => clearTimeout(t);
-  }, [lastMessageId, selectedRoomId]);
+  }, [lastMessageId, selectedRoomId, isOpen]);
 
   // Re-attach scroll listener whenever room changes (scrollRef mounts after room is set)
   useEffect(() => {