feat(chat-room): 채팅방 리스트 응답 개선(타입/미리보기/상대 이미지/시간)

- ChatRoomListQueryDto: characterType, lastActivityAt 필드 추가
- ChatRoomListItemDto: opponentType, lastMessagePreview, lastMessageTimeLabel 제공
- 레포지토리 정렬 기준을 최근 메시지 또는 생성일로 일원화(COALESCE)

src/main/kotlin/kr/co/vividnext/sodalive/chat/room/dto/ChatRoomDto.kt

@@ -2,6 +2,8 @@ package kr.co.vividnext.sodalive.chat.room.dto
 
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties
 import com.fasterxml.jackson.annotation.JsonProperty
+import kr.co.vividnext.sodalive.chat.character.CharacterType
+import java.time.LocalDateTime
 
 /**
  * 채팅방 생성 요청 DTO
@@ -24,7 +26,9 @@ data class ChatRoomListItemDto(
     val chatRoomId: Long,
     val title: String,
     val imageUrl: String,
-    val lastMessagePreview: String?
+    val opponentType: String,
+    val lastMessagePreview: String?,
+    val lastMessageTimeLabel: String
 )
 
 /**
@@ -40,10 +44,13 @@ data class ChatMessageItemDto(
 /**
  * 채팅방 목록 쿼리 DTO (레포지토리 투영용)
  */
+
 data class ChatRoomListQueryDto(
     val chatRoomId: Long,
     val title: String,
-    val imagePath: String?
+    val imagePath: String?,
+    val characterType: CharacterType,
+    val lastActivityAt: LocalDateTime?
 )
 
 /**

src/main/kotlin/kr/co/vividnext/sodalive/chat/room/repository/ChatRoomRepository.kt

@@ -40,7 +40,9 @@ interface ChatRoomRepository : JpaRepository<ChatRoom, Long> {
             SELECT new kr.co.vividnext.sodalive.chat.room.dto.ChatRoomListQueryDto(
                 r.id,
                 r.title,
-                pc.character.imagePath
+                pc.character.imagePath,
+                pc.character.characterType,
+                COALESCE(MAX(m.createdAt), r.createdAt)
             )
             FROM ChatRoom r
             JOIN r.participants p

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

@@ -199,18 +199,39 @@ class ChatRoomService(
 
             val latest = messageRepository.findTopByChatRoomAndIsActiveTrueOrderByCreatedAtDesc(room)
             val preview = latest?.message?.let { msg ->
-                if (msg.length <= 25) msg else msg.take(25) + "..."
+                if (msg.length <= 30) msg else msg.take(30) + "..."
             }
 
+            val imageUrl = "$imageHost/${q.imagePath ?: "profile/default-profile.png"}"
+            val opponentType = q.characterType.name // Clone or Character
+            val time = latest?.createdAt ?: q.lastActivityAt
+            val timeLabel = formatRelativeTime(time)
+
             ChatRoomListItemDto(
                 chatRoomId = q.chatRoomId,
                 title = q.title,
-                imageUrl = "$imageHost/${q.imagePath ?: "profile/default-profile.png"}",
+                imageUrl = imageUrl,
-                lastMessagePreview = preview
+                opponentType = opponentType,
+                lastMessagePreview = preview,
+                lastMessageTimeLabel = timeLabel
             )
         }
     }
 
+    private fun formatRelativeTime(time: java.time.LocalDateTime?): String {
+        if (time == null) return ""
+        val now = java.time.LocalDateTime.now()
+        val duration = java.time.Duration.between(time, now)
+        val seconds = duration.seconds
+        if (seconds <= 60) return "방금"
+        val minutes = duration.toMinutes()
+        if (minutes < 60) return "${'$'}minutes분 전"
+        val hours = duration.toHours()
+        if (hours < 24) return "${'$'}hours시간 전"
+        // 그 외: 날짜 (yyyy-MM-dd)
+        return time.toLocalDate().toString()
+    }
+
     @Transactional(readOnly = true)
     fun isMyRoomSessionActive(member: Member, chatRoomId: Long): Boolean {
         val room = chatRoomRepository.findById(chatRoomId).orElseThrow {