feat(chat-banner): 다국어 캐릭터 배너 등록과 노출을 지원한다

배너를 언어별로 저장하고 요청 언어 우선 조회 후 한국어로 fallback 하도록 맞춘다.

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

@@ -1,7 +1,11 @@
 package kr.co.vividnext.sodalive.chat.character
 
 import kr.co.vividnext.sodalive.common.BaseEntity
+import kr.co.vividnext.sodalive.i18n.Lang
+import javax.persistence.Column
 import javax.persistence.Entity
+import javax.persistence.EnumType
+import javax.persistence.Enumerated
 import javax.persistence.FetchType
 import javax.persistence.JoinColumn
 import javax.persistence.ManyToOne
@@ -24,6 +28,10 @@ class ChatCharacterBanner(
     // 정렬 순서 (낮을수록 먼저 표시)
     var sortOrder: Int = 0,
 
+    @Column(nullable = false)
+    @Enumerated(EnumType.STRING)
+    var lang: Lang = Lang.KO,
+
     // 활성화 여부 (소프트 삭제용)
     var isActive: Boolean = true
 ) : BaseEntity()

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

@@ -62,7 +62,7 @@ class ChatCharacterController(
         val isAdultAccessible = resolveIsAdultAccessible(member)
 
         // 배너 조회 (최대 10개)
-        val banners = bannerService.getActiveBanners(PageRequest.of(0, 10))
+        val banners = bannerService.getDisplayBanners(PageRequest.of(0, 10), langContext.lang)
             .content
             .map {
                 CharacterBannerResponse(

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

@@ -1,6 +1,7 @@
 package kr.co.vividnext.sodalive.chat.character.repository
 
 import kr.co.vividnext.sodalive.chat.character.ChatCharacterBanner
+import kr.co.vividnext.sodalive.i18n.Lang
 import org.springframework.data.domain.Page
 import org.springframework.data.domain.Pageable
 import org.springframework.data.jpa.repository.JpaRepository
@@ -12,6 +13,8 @@ interface ChatCharacterBannerRepository : JpaRepository<ChatCharacterBanner, Lon
     // 활성화된 배너 목록 조회 (정렬 순서대로)
     fun findByIsActiveTrueOrderBySortOrderAsc(pageable: Pageable): Page<ChatCharacterBanner>
 
+    fun findByIsActiveTrueAndLangOrderBySortOrderAsc(lang: Lang, pageable: Pageable): Page<ChatCharacterBanner>
+
     // 활성화된 배너 중 최대 정렬 순서 값 조회
     @Query("SELECT MAX(b.sortOrder) FROM ChatCharacterBanner b WHERE b.isActive = true")
     fun findMaxSortOrder(): Int?

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

@@ -4,6 +4,7 @@ import kr.co.vividnext.sodalive.chat.character.ChatCharacterBanner
 import kr.co.vividnext.sodalive.chat.character.repository.ChatCharacterBannerRepository
 import kr.co.vividnext.sodalive.chat.character.repository.ChatCharacterRepository
 import kr.co.vividnext.sodalive.common.SodaException
+import kr.co.vividnext.sodalive.i18n.Lang
 import org.springframework.data.domain.Page
 import org.springframework.data.domain.Pageable
 import org.springframework.stereotype.Service
@@ -21,6 +22,19 @@ class ChatCharacterBannerService(
         return bannerRepository.findByIsActiveTrueOrderBySortOrderAsc(pageable)
     }
 
+    fun getDisplayBanners(pageable: Pageable, lang: Lang): Page<ChatCharacterBanner> {
+        if (lang == Lang.KO) {
+            return bannerRepository.findByIsActiveTrueAndLangOrderBySortOrderAsc(Lang.KO, pageable)
+        }
+
+        val localizedBanners = bannerRepository.findByIsActiveTrueAndLangOrderBySortOrderAsc(lang, pageable)
+        return if (localizedBanners.hasContent()) {
+            localizedBanners
+        } else {
+            bannerRepository.findByIsActiveTrueAndLangOrderBySortOrderAsc(Lang.KO, pageable)
+        }
+    }
+
     /**
      * 배너 상세 조회
      */
@@ -37,7 +51,10 @@ class ChatCharacterBannerService(
      * @return 등록된 배너
      */
     @Transactional
-    fun registerBanner(characterId: Long, imagePath: String): ChatCharacterBanner {
+    fun registerBanner(characterId: Long, imagePath: String, lang: Lang? = null): ChatCharacterBanner {
+        val finalLang = lang ?: Lang.KO
+        validateRegisterLang(finalLang)
+
         val character = characterRepository.findById(characterId)
             .orElseThrow { SodaException(messageKey = "chat.character.not_found") }
 
@@ -51,12 +68,21 @@ class ChatCharacterBannerService(
         val banner = ChatCharacterBanner(
             imagePath = imagePath,
             chatCharacter = character,
-            sortOrder = finalSortOrder
+            sortOrder = finalSortOrder,
+            lang = finalLang
         )
 
         return bannerRepository.save(banner)
     }
 
+    private fun validateRegisterLang(lang: Lang) {
+        if (lang == Lang.KO || lang == Lang.EN || lang == Lang.JA) {
+            return
+        }
+
+        throw SodaException(messageKey = "common.error.invalid_request")
+    }
+
     /**
      * 배너 수정
      *