feat(be): AI챗 레포지토리 구현

Author: Mrbaeksang

src/main/kotlin/com/back/koreaTravelGuide/domain/ai/aiChat/repository/AiChatMessageRepository.kt

@@ -0,0 +1,8 @@
+package com.back.koreaTravelGuide.domain.ai.aiChat.repository
+
+import com.back.koreaTravelGuide.domain.ai.aiChat.entity.AiChatMessage
+import org.springframework.data.jpa.repository.JpaRepository
+
+interface AiChatMessageRepository : JpaRepository<AiChatMessage, Long> {
+    fun findByAiChatSessionIdOrderByCreatedAtAsc(sessionId: Long): List<AiChatMessage>
+}

src/main/kotlin/com/back/koreaTravelGuide/domain/ai/aiChat/repository/AiChatSessionRepository.kt

@@ -0,0 +1,15 @@
+package com.back.koreaTravelGuide.domain.ai.aiChat.repository
+
+import com.back.koreaTravelGuide.domain.ai.aiChat.entity.AiChatSession
+import org.springframework.data.jpa.repository.JpaRepository
+
+interface AiChatSessionRepository : JpaRepository<AiChatSession, Long> {
+    // 사용자별 세션 조회 (최신순)
+    fun findByUserIdOrderByCreatedAtDesc(userId: Long): List<AiChatSession>
+
+    // 세션 아이디와 사용자 아이디로 세션 조회 (삭제 권한 체크)
+    fun findByIdAndUserId(
+        sessionId: Long,
+        userId: Long,
+    ): AiChatSession?
+}