perf(explorer:creator-profile): 라이브방 목록 N+1 제거 및 예약/결제 여부 일괄 조회

- member 연관 로딩에 fetch join 적용으로 N+1 제거
- reservations 컬렉션 접근 제거 → QLiveReservation 기반 방 ID 일괄 조회로 isReservation 계산
- useCan per-room 조회 제거 → 방 ID 집합 일괄 조회(Set)로 isPaid 계산
- 기존 비즈니스 로직(날짜 포맷, 성인/성별 필터, PRIVATE 플래그 등) 유지

src/main/kotlin/kr/co/vividnext/sodalive/explorer/ExplorerQueryRepository.kt

@@ -23,6 +23,7 @@ import kr.co.vividnext.sodalive.extensions.removeDeletedNicknamePrefix
 import kr.co.vividnext.sodalive.i18n.Lang
 import kr.co.vividnext.sodalive.i18n.LangContext
 import kr.co.vividnext.sodalive.i18n.SodaMessageSource
+import kr.co.vividnext.sodalive.live.reservation.QLiveReservation
 import kr.co.vividnext.sodalive.live.room.GenderRestriction
 import kr.co.vividnext.sodalive.live.room.LiveRoom
 import kr.co.vividnext.sodalive.live.room.LiveRoomType
@@ -374,7 +375,7 @@ class ExplorerQueryRepository(
             result.addAll(
                 queryFactory
                     .selectFrom(liveRoom)
-                    .innerJoin(liveRoom.member, member)
+                    .innerJoin(liveRoom.member, member).fetchJoin()
                     .leftJoin(liveRoom.cancel, liveRoomCancel)
                     .where(where)
                     .orderBy(liveRoom.beginDateTime.asc())
@@ -388,13 +389,43 @@ class ExplorerQueryRepository(
         val dateTimeFormatter = DateTimeFormatter.ofPattern(dateTimePattern)
             .withLocale(langContext.lang.locale)
 
-        return result
-            .map {
-                val reservations = it.reservations
-                    .filter { reservation ->
-                        reservation.member!!.id!! == userMember.id!! && reservation.isActive
+        // N+1 방지: 한 번에 필요한 정보 일괄 조회
+        val roomIds = result.mapNotNull { it.id }.toSet()
+        if (roomIds.isEmpty()) {
+            return emptyList()
         }
 
+        // 사용자 예약 여부를 방 ID 기준으로 일괄 조회
+        val reservationRoomIdSet: Set<Long> = run {
+            // Q 클래스는 의존 파일들에서 사용되는 패턴을 맞춰 import 없이 정규 참조
+            val resIds = queryFactory
+                .select(QLiveReservation.liveReservation.room.id)
+                .from(QLiveReservation.liveReservation)
+                .where(
+                    QLiveReservation.liveReservation.room.id.`in`(roomIds)
+                        .and(QLiveReservation.liveReservation.member.id.eq(userMember.id))
+                        .and(QLiveReservation.liveReservation.isActive.isTrue)
+                )
+                .fetch()
+            resIds.filterNotNull().toSet()
+        }
+
+        // 결제 여부를 방 ID 기준으로 일괄 조회 (CanUsage.LIVE)
+        val paidRoomIdSet: Set<Long> = run {
+            val ids = queryFactory
+                .select(useCan.room.id)
+                .from(useCan)
+                .where(
+                    useCan.room.id.`in`(roomIds)
+                        .and(useCan.canUsage.eq(CanUsage.LIVE))
+                )
+                .groupBy(useCan.room.id)
+                .fetch()
+            ids.filterNotNull().toSet()
+        }
+
+        return result
+            .map {
                 val beginDateTime = it.beginDateTime
                     .atZone(ZoneId.of("UTC"))
                     .withZoneSameInstant(ZoneId.of(timezone))
@@ -403,22 +434,7 @@ class ExplorerQueryRepository(
                 val beginDateTimeUtc = it.beginDateTime
                     .format(DateTimeFormatter.ISO_LOCAL_DATE_TIME)
 
-                val isPaid = if (it.channelName != null) {
-                    val useCan = queryFactory
-                        .selectFrom(useCan)
-                        .innerJoin(useCan.member, member)
-                        .where(
-                            useCan.member.id.eq(member.id)
-                                .and(useCan.room.id.eq(it.id!!))
-                                .and(useCan.canUsage.eq(CanUsage.LIVE))
-                        )
-                        .orderBy(useCan.id.desc())
-                        .fetchFirst()
-
-                    useCan != null
-                } else {
-                    false
-                }
+                val isPaid = it.channelName != null && paidRoomIdSet.contains(it.id!!)
 
                 LiveRoomResponse(
                     roomId = it.id!!,
@@ -441,7 +457,7 @@ class ExplorerQueryRepository(
                             else -> "$cloudFrontHost/$profileImage"
                         }
                     },
-                    isReservation = reservations.isNotEmpty(),
+                    isReservation = reservationRoomIdSet.contains(it.id!!),
                     isActive = it.isActive,
                     isPrivateRoom = it.type == LiveRoomType.PRIVATE
                 )