홈 크리에이터 랭킹 팔로우 조회 최적화

홈 API의 크리에이터 랭킹 응답에서 팔로우 여부를 일괄 조회로 계산한다.

src/main/kotlin/kr/co/vividnext/sodalive/api/home/HomeService.kt

@@ -82,18 +82,20 @@ class HomeService(
             timezone = timezone
         )
 
-        val creatorRanking = rankingRepository
-            .getCreatorRankings(memberId = memberId)
-            .map {
-                val followerCount = explorerQueryRepository.getNotificationUserIds(it.id!!).size
-                val follow = if (memberId != null) {
-                    explorerQueryRepository.isFollow(it.id!!, memberId = memberId)
-                } else {
-                    false
-                }
+        val creatorRankingMembers = rankingRepository.getCreatorRankings(memberId = memberId)
+        val creatorRankingIds = creatorRankingMembers.mapNotNull { it.id }
+        val followedCreatorIds = if (memberId != null) {
+            explorerQueryRepository.getFollowedCreatorIds(creatorRankingIds, memberId)
+        } else {
+            emptySet()
+        }
 
-                it.toExplorerSectionCreator(imageHost, follow, followerCount = followerCount)
-            }
+        val creatorRanking = creatorRankingMembers.map { creator ->
+            val creatorId = creator.id!!
+            val follow = memberId != null && followedCreatorIds.contains(creatorId)
+
+            creator.toExplorerSectionCreator(imageHost, follow)
+        }
 
         val latestContentThemeList = contentThemeService.getActiveThemeOfContent(
             isAdult = isAdult,