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/rank/RankingRepository.kt

@@ -69,7 +69,8 @@ class RankingRepository(
         offset: Long,
         limit: Long,
         sortType: String,
-        theme: String = ""
+        theme: String = "",
+        locale: String? = null
     ): List<GetAudioContentRankingItem> {
         val blockMemberCondition = if (memberId != null) {
             blockMember.member.id.eq(member.id)
@@ -79,6 +80,8 @@ class RankingRepository(
             null
         }
 
+        val contentTranslation = kr.co.vividnext.sodalive.content.translation.QContentTranslation.contentTranslation
+
         var where = audioContent.isActive.isTrue
             .and(audioContent.member.isActive.isTrue)
             .and(audioContent.member.isNotNull)
@@ -109,11 +112,26 @@ class RankingRepository(
             where = where.and(audioContentTheme.theme.eq(theme))
         }
 
+        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(
                 QGetAudioContentRankingItem(
                     audioContent.id,
-                    audioContent.title,
+                    titleExpression,
                     audioContent.coverImage.prepend("/").prepend(imageHost),
                     audioContentTheme.theme,
                     audioContent.price,
@@ -167,6 +185,11 @@ class RankingRepository(
             }
         }
 
+        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/rank/RankingService.kt

@@ -9,6 +9,7 @@ import kr.co.vividnext.sodalive.creator.admin.content.series.Series
 import kr.co.vividnext.sodalive.creator.admin.content.series.SeriesPublishedDaysOfWeek
 import kr.co.vividnext.sodalive.creator.admin.content.series.SeriesState
 import kr.co.vividnext.sodalive.explorer.GetExplorerSectionResponse
+import kr.co.vividnext.sodalive.i18n.LangContext
 import org.springframework.beans.factory.annotation.Value
 import org.springframework.stereotype.Service
 import java.time.LocalDateTime
@@ -17,6 +18,7 @@ import java.time.LocalDateTime
 class RankingService(
     private val repository: RankingRepository,
     private val seriesContentRepository: ContentSeriesContentRepository,
+    private val langContext: LangContext,
 
     @Value("\${cloud.aws.cloud-front.host}")
     private val imageHost: String
@@ -59,7 +61,8 @@ class RankingService(
                 offset = offset,
                 limit = limit,
                 sortType = sortType,
-                theme = theme
+                theme = theme,
+                locale = langContext.lang.code
             )
             loopCount++
         } while (contentList.size < 5 && loopCount < 5)