HomeService fetchData 리팩토링 및 DB JOIN 기반 번역 적용

fetchData 함수에서 별도로 수행하던 번역 데이터 조회를 DB JOIN 및
COALESCE를 사용하도록 개선하여 성능을 최적화함.

- AudioContentRepository, RankingRepository 등에 locale 파라미터 추가
- DB 레벨에서 번역된 제목을 조회하도록 쿼리 수정
- HomeService에서 불필요한 getTranslatedContentList 호출 제거

src/main/kotlin/kr/co/vividnext/sodalive/query/recommend/RecommendChannelQueryRepository.kt

@@ -6,6 +6,7 @@ import kr.co.vividnext.sodalive.content.ContentType
 import kr.co.vividnext.sodalive.content.QAudioContent.audioContent
 import kr.co.vividnext.sodalive.content.comment.QAudioContentComment.audioContentComment
 import kr.co.vividnext.sodalive.content.like.QAudioContentLike.audioContentLike
+import kr.co.vividnext.sodalive.content.translation.QContentTranslation.contentTranslation
 import kr.co.vividnext.sodalive.member.MemberRole
 import kr.co.vividnext.sodalive.member.QMember.member
 import kr.co.vividnext.sodalive.member.auth.QAuth.auth
@@ -83,7 +84,8 @@ class RecommendChannelQueryRepository(
     fun getContentsByCreatorIdLikeDesc(
         creatorId: Long,
         memberId: Long?,
-        isAdult: Boolean
+        isAdult: Boolean,
+        locale: String? = null
     ): List<RecommendChannelContentItem> {
         val blockMemberCondition = if (memberId != null) {
             blockMember.member.id.eq(audioContent.member.id)
@@ -99,11 +101,26 @@ class RecommendChannelQueryRepository(
             where = where.and(audioContent.isAdult.isFalse)
         }
 
+        val titleExpression = if (locale != null) {
+            val translatedTitle = Expressions.stringTemplate(
+                "JSON_EXTRACT({0}, '$.title')",
+                contentTranslation.renderedPayload
+            )
+            val coalesceTitle = Expressions.stringTemplate(
+                "COALESCE(NULLIF({0}, ''), {1})",
+                translatedTitle,
+                audioContent.title
+            )
+            coalesceTitle
+        } else {
+            audioContent.title
+        }
+
         var select = queryFactory
             .select(
                 QRecommendChannelContentItem(
                     audioContent.id,
-                    audioContent.title,
+                    titleExpression,
                     audioContent.coverImage.prepend("/").prepend(imageHost),
                     audioContentLike.id.countDistinct(),
                     audioContentComment.id.countDistinct()
@@ -121,6 +138,14 @@ class RecommendChannelQueryRepository(
                     .and(audioContentComment.isActive.isTrue)
             )
 
+        if (locale != null) {
+            select = select.leftJoin(contentTranslation)
+                .on(
+                    contentTranslation.contentId.eq(audioContent.id)
+                        .and(contentTranslation.locale.eq(locale))
+                )
+        }
+
         if (memberId != null) {
             where = where.and(blockMember.id.isNull)
             select = select.leftJoin(blockMember).on(blockMemberCondition)

src/main/kotlin/kr/co/vividnext/sodalive/query/recommend/RecommendChannelQueryService.kt

@@ -1,13 +1,17 @@
 package kr.co.vividnext.sodalive.query.recommend
 
 import kr.co.vividnext.sodalive.content.ContentType
+import kr.co.vividnext.sodalive.i18n.LangContext
 import org.springframework.cache.annotation.Cacheable
 import org.springframework.stereotype.Service
 import org.springframework.transaction.annotation.Transactional
 
 @Service
 @Transactional(readOnly = true)
-class RecommendChannelQueryService(private val repository: RecommendChannelQueryRepository) {
+class RecommendChannelQueryService(
+    private val repository: RecommendChannelQueryRepository,
+    private val langContext: LangContext
+) {
     @Cacheable(
         cacheNames = ["default"],
         key = "'recommendChannel:' + (#memberId ?: 'guest') + ':' + #isAdult + ':' + #contentType"
@@ -27,7 +31,8 @@ class RecommendChannelQueryService(private val repository: RecommendChannelQuery
             it.contentList = repository.getContentsByCreatorIdLikeDesc(
                 creatorId = it.channelId,
                 memberId = memberId,
-                isAdult = isAdult
+                isAdult = isAdult,
+                locale = langContext.lang.code
             )
 
             it