feat(home): AI 캐릭터 빈 스냅샷 마커를 저장한다

src/test/kotlin/kr/co/vividnext/sodalive/v2/recommendation/adapter/out/persistence/RecommendationSnapshotPersistenceAdapterTest.kt

@@ -108,6 +108,40 @@ class RecommendationSnapshotPersistenceAdapterTest @Autowired constructor(
         assertEquals(3, repository.findAll().size)
     }
 
+    @Test
+    fun shouldClearAiCharacterSectionSnapshotsWhenReplacingWithEmptySnapshots() {
+        val oldSnapshotAt = LocalDateTime.of(2026, 5, 28, 23, 59, 59)
+        val snapshotAt = LocalDateTime.of(2026, 5, 29, 23, 59, 59)
+        repository.saveAll(
+            listOf(
+                snapshot(RecommendedSectionType.AI_CHARACTER, targetId = 1L, score = 100.0, snapshotAt = oldSnapshotAt),
+                snapshot(RecommendedSectionType.CHEER_CREATOR, targetId = 2L, score = 200.0, snapshotAt = oldSnapshotAt)
+            )
+        )
+
+        adapter.replaceSnapshots(RecommendedSectionType.AI_CHARACTER, snapshotAt, emptyList())
+
+        assertEquals(emptyList<RecommendationSnapshotRecord>(), adapter.findLatestSnapshots(RecommendedSectionType.AI_CHARACTER))
+        assertEquals(listOf(2L), adapter.findLatestSnapshots(RecommendedSectionType.CHEER_CREATOR).map { it.targetId })
+        assertEquals(true, adapter.existsLatestSnapshot(RecommendedSectionType.AI_CHARACTER))
+        assertEquals(
+            listOf(0L),
+            repository.findAll()
+                .filter { it.sectionType == RecommendedSectionType.AI_CHARACTER }
+                .map { it.targetId }
+        )
+    }
+
+    @Test
+    fun shouldExcludeEmptySnapshotMarkerFromLatestSnapshotResults() {
+        val snapshotAt = LocalDateTime.of(2026, 5, 29, 23, 59, 59)
+
+        adapter.replaceSnapshots(RecommendedSectionType.AI_CHARACTER, snapshotAt, emptyList())
+
+        assertEquals(emptyList<RecommendationSnapshotRecord>(), adapter.findLatestSnapshots(RecommendedSectionType.AI_CHARACTER))
+        assertEquals(true, adapter.existsLatestSnapshot(RecommendedSectionType.AI_CHARACTER))
+    }
+
     private fun snapshot(
         sectionType: RecommendedSectionType,
         targetId: Long,