fix(chat-room): 채팅방 입장

- AI 채팅 쿼터 Lazy refill 적용을 위해 read/write 모두 가능하도록 Transaction 수정

src/main/kotlin/kr/co/vividnext/sodalive/chat/room/service/ChatRoomService.kt

@@ -297,7 +297,7 @@ class ChatRoomService(
         return fetchSessionActive(room.sessionId)
     }
 
-    @Transactional(readOnly = true)
+    @Transactional
     fun enterChatRoom(member: Member, chatRoomId: Long): ChatRoomEnterResponse {
         val room = chatRoomRepository.findById(chatRoomId).orElseThrow {
             SodaException("채팅방을 찾을 수 없습니다.")