feat(chat-character): 캐릭터 상세 조회 응답 확장 및 ‘다른 캐릭터’ 추천 추가

- 상세 페이지 정보 강화 및 탐색성 향상을 위해 응답 필드를 확장
- CharacterDetailResponse에 originalTitle, originalLink, characterType, others 추가
- OtherCharacter DTO 추가 (characterId, name, imageUrl, tags)
- 공유 태그 기반으로 현재 캐릭터를 제외한 랜덤 10개 캐릭터 조회 JPA 쿼리 추가
  - ChatCharacterRepository.findRandomBySharedTags(@Query, RAND 정렬, 페이징)
- 서비스 계층에 getOtherCharactersBySharedTags 추가 및 태그 지연 로딩 초기화
- 컨트롤러에서:
  - others 리스트를 조회/매핑하여 응답에 포함
  - originalTitle, originalLink, characterType을 응답에 포함

src/main/kotlin/kr/co/vividnext/sodalive/chat/character/controller/ChatCharacterController.kt

@@ -7,6 +7,7 @@ import kr.co.vividnext.sodalive.chat.character.dto.CharacterDetailResponse
 import kr.co.vividnext.sodalive.chat.character.dto.CharacterMainResponse
 import kr.co.vividnext.sodalive.chat.character.dto.CharacterPersonalityResponse
 import kr.co.vividnext.sodalive.chat.character.dto.CurationSection
+import kr.co.vividnext.sodalive.chat.character.dto.OtherCharacter
 import kr.co.vividnext.sodalive.chat.character.dto.RecentCharacter
 import kr.co.vividnext.sodalive.chat.character.service.ChatCharacterBannerService
 import kr.co.vividnext.sodalive.chat.character.service.ChatCharacterService
@@ -127,6 +128,20 @@ class ChatCharacterController(
             )
         }
 
+        // 다른 캐릭터 조회 (태그 기반, 랜덤 10개, 현재 캐릭터 제외)
+        val others = service.getOtherCharactersBySharedTags(characterId, 10)
+            .map { other ->
+                val otherTags = other.tagMappings
+                    .map { it.tag.tag }
+                    .joinToString(" ") { if (it.startsWith("#")) it else "#$it" }
+                OtherCharacter(
+                    characterId = other.id!!,
+                    name = other.name,
+                    imageUrl = "$imageHost/${other.imagePath ?: "profile/default-profile.png"}",
+                    tags = otherTags
+                )
+            }
+
         // 응답 생성
         ApiResponse.ok(
             CharacterDetailResponse(
@@ -137,7 +152,11 @@ class ChatCharacterController(
                 imageUrl = "$imageHost/${character.imagePath ?: "profile/default-profile.png"}",
                 personalities = personality,
                 backgrounds = background,
-                tags = tags
+                tags = tags,
+                originalTitle = character.originalTitle,
+                originalLink = character.originalLink,
+                characterType = character.characterType,
+                others = others
             )
         )
     }

src/main/kotlin/kr/co/vividnext/sodalive/chat/character/dto/CharacterDetailResponse.kt

@@ -1,5 +1,7 @@
 package kr.co.vividnext.sodalive.chat.character.dto
 
+import kr.co.vividnext.sodalive.chat.character.CharacterType
+
 data class CharacterDetailResponse(
     val characterId: Long,
     val name: String,
@@ -8,6 +10,17 @@ data class CharacterDetailResponse(
     val imageUrl: String,
     val personalities: CharacterPersonalityResponse?,
     val backgrounds: CharacterBackgroundResponse?,
+    val tags: String,
+    val originalTitle: String?,
+    val originalLink: String?,
+    val characterType: CharacterType,
+    val others: List<OtherCharacter>
+)
+
+data class OtherCharacter(
+    val characterId: Long,
+    val name: String,
+    val imageUrl: String,
     val tags: String
 )
 

src/main/kotlin/kr/co/vividnext/sodalive/chat/character/repository/ChatCharacterRepository.kt

@@ -66,4 +66,25 @@ interface ChatCharacterRepository : JpaRepository<ChatCharacter, Long> {
         @Param("member") member: Member,
         pageable: Pageable
     ): List<ChatCharacter>
+
+    /**
+     * 특정 캐릭터와 태그를 공유하는 다른 캐릭터를 무작위로 조회 (현재 캐릭터 제외)
+     */
+    @Query(
+        """
+        SELECT DISTINCT c FROM ChatCharacter c
+        JOIN c.tagMappings tm
+        JOIN tm.tag t
+        WHERE c.isActive = true
+          AND c.id <> :characterId
+          AND t.id IN (
+            SELECT t2.id FROM ChatCharacterTagMapping tm2 JOIN tm2.tag t2 WHERE tm2.chatCharacter.id = :characterId
+          )
+        ORDER BY function('RAND')
+        """
+    )
+    fun findRandomBySharedTags(
+        @Param("characterId") characterId: Long,
+        pageable: Pageable
+    ): List<ChatCharacter>
 }

src/main/kotlin/kr/co/vividnext/sodalive/chat/character/service/ChatCharacterService.kt

@@ -53,6 +53,20 @@ class ChatCharacterService(
         return chatCharacterRepository.findByIsActiveTrueOrderByCreatedAtDesc(PageRequest.of(0, limit))
     }
 
+    /**
+     * 특정 캐릭터와 태그를 공유하는 다른 캐릭터를 무작위로 조회 (현재 캐릭터 제외)
+     */
+    @Transactional(readOnly = true)
+    fun getOtherCharactersBySharedTags(characterId: Long, limit: Int = 10): List<ChatCharacter> {
+        val others = chatCharacterRepository.findRandomBySharedTags(
+            characterId,
+            PageRequest.of(0, limit)
+        )
+        // 태그 초기화 (지연 로딩 문제 방지)
+        others.forEach { it.tagMappings.size }
+        return others
+    }
+
     /**
      * 태그를 찾거나 생성하여 캐릭터에 연결
      */