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/content/AudioContentRepository.kt

@@ -25,6 +25,7 @@ import kr.co.vividnext.sodalive.content.pin.QPinContent.pinContent
 import kr.co.vividnext.sodalive.content.playlist.AudioContentPlaylistContent
 import kr.co.vividnext.sodalive.content.playlist.QAudioContentPlaylistContent
 import kr.co.vividnext.sodalive.content.theme.QAudioContentTheme.audioContentTheme
+import kr.co.vividnext.sodalive.content.translation.QContentTranslation.contentTranslation
 import kr.co.vividnext.sodalive.creator.admin.content.series.QSeries.series
 import kr.co.vividnext.sodalive.creator.admin.content.series.QSeriesContent.seriesContent
 import kr.co.vividnext.sodalive.event.QEvent.event
@@ -188,7 +189,8 @@ interface AudioContentQueryRepository {
         isAdult: Boolean,
         orderByRandom: Boolean = false,
         isPointAvailableOnly: Boolean = false,
-        excludeContentIds: List<Long> = emptyList()
+        excludeContentIds: List<Long> = emptyList(),
+        locale: String? = null
     ): List<AudioContentMainItem>
 
     fun findContentByCurationId(
@@ -1331,7 +1333,8 @@ class AudioContentQueryRepositoryImpl(
         isAdult: Boolean,
         orderByRandom: Boolean,
         isPointAvailableOnly: Boolean,
-        excludeContentIds: List<Long>
+        excludeContentIds: List<Long>,
+        locale: String?
     ): List<AudioContentMainItem> {
         val blockMemberCondition = if (memberId != null) {
             blockMember.member.id.eq(member.id)
@@ -1382,12 +1385,27 @@ class AudioContentQueryRepositoryImpl(
             where = where.and(audioContent.id.notIn(excludeContentIds))
         }
 
+        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(
                 QAudioContentMainItem(
                     audioContent.id,
                     member.id,
-                    audioContent.title,
+                    titleExpression,
                     audioContent.coverImage.prepend("/").prepend(imageHost),
                     member.nickname,
                     audioContent.isPointAvailable
@@ -1397,6 +1415,11 @@ class AudioContentQueryRepositoryImpl(
             .innerJoin(audioContent.member, member)
             .innerJoin(audioContent.theme, audioContentTheme)
 
+        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/content/AudioContentService.kt

@@ -1222,7 +1222,7 @@ class AudioContentService(
             isPointAvailableOnly = isPointAvailableOnly
         )
 
-        val contentList = repository.getLatestContentByTheme(
+        return repository.getLatestContentByTheme(
             memberId = memberId,
             theme = normalizedTheme,
             contentType = contentType,
@@ -1233,26 +1233,9 @@ class AudioContentService(
             isAdult = isAdult,
             orderByRandom = orderByRandom,
             isPointAvailableOnly = isPointAvailableOnly,
-            excludeContentIds = excludeContentIds
+            excludeContentIds = excludeContentIds,
+            locale = langContext.lang.code
         )
-
-        val contentIds = contentList.map { it.contentId }
-        return if (contentIds.isNotEmpty()) {
-            val translations = contentTranslationRepository
-                .findByContentIdInAndLocale(contentIds = contentIds, locale = langContext.lang.code)
-                .associateBy { it.contentId }
-
-            contentList.map { item ->
-                val translatedTitle = translations[item.contentId]?.renderedPayload?.title
-                if (translatedTitle.isNullOrBlank()) {
-                    item
-                } else {
-                    item.copy(title = translatedTitle)
-                }
-            }
-        } else {
-            contentList
-        }
     }
 
     /**