feat: 즐겨찾기 기능 데이터 레이어 추가

- HotDeal, HotDealEntity에 isFavorite 필드 추가
- HotDealDao에 즐겨찾기 관련 쿼리 메서드 추가
- 데이터베이스 마이그레이션 (v3 -> v4) 추가

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

app/src/main/java/com/hotdeal/alarm/data/local/db/AppDatabase.kt

@@ -21,7 +21,7 @@ import com.hotdeal.alarm.data.local.db.entity.SiteConfigEntity
         SiteConfigEntity::class,
         KeywordEntity::class
     ],
-    version = 3,
+ version = 4,
     exportSchema = false
 )
 @TypeConverters(Converters::class)
@@ -51,6 +51,14 @@ abstract class AppDatabase : RoomDatabase() {
  db.execSQL("CREATE INDEX IF NOT EXISTS index_hot_deals_siteName_boardName ON hot_deals(siteName, boardName)")
  db.execSQL("CREATE INDEX IF NOT EXISTS index_hot_deals_createdAt ON hot_deals(createdAt)")
  }
+ }
+
+ /**
+ * Migration 3 -> 4: 즐겨찾기 필드 추가
+ */
+ val MIGRATION_3_4 = object : Migration(3, 4) {
+ override fun migrate(db: SupportSQLiteDatabase) {
+ db.execSQL("ALTER TABLE hot_deals ADD COLUMN isFavorite INTEGER NOT NULL DEFAULT 0")
  }
     }
 }

app/src/main/java/com/hotdeal/alarm/data/local/db/dao/HotDealDao.kt

@@ -99,4 +99,26 @@ interface HotDealDao {
      */
  @Query("SELECT * FROM hot_deals WHERE title LIKE '%' || :query || '%' ORDER BY createdAt DESC")
  fun searchDeals(query: String): Flow<List<HotDealEntity>>
+
+ // =========================
+ // 즐겨찾기 관련 메서드
+ // =========================
+
+ /**
+ * 즐겨찾기 핫딜 조회
+ */
+ @Query("SELECT * FROM hot_deals WHERE isFavorite = 1 ORDER BY createdAt DESC")
+ fun observeFavoriteDeals(): Flow<List<HotDealEntity>>
+
+ /**
+ * 즐겨찾기 상태 토글
+ */
+ @Query("UPDATE hot_deals SET isFavorite = NOT isFavorite WHERE id = :id")
+ suspend fun toggleFavorite(id: String)
+
+ /**
+ * 즐겨찾기 상태 설정
+ */
+ @Query("UPDATE hot_deals SET isFavorite = :isFavorite WHERE id = :id")
+ suspend fun setFavorite(id: String, isFavorite: Boolean)
 }

app/src/main/java/com/hotdeal/alarm/data/local/db/entity/HotDealEntity.kt

@@ -25,7 +25,8 @@ data class HotDealEntity(
     val mallUrl: String?,
  val createdAt: Long,
  val isNotified: Boolean = false,
-    val isKeywordMatch: Boolean = false
+ val isKeywordMatch: Boolean = false,
+ val isFavorite: Boolean = false // 즐겨찾기 여부
 ) {
     /**
      * Domain 모델로 변환
@@ -40,7 +41,8 @@ data class HotDealEntity(
             mallUrl = mallUrl,
             createdAt = createdAt,
  isNotified = isNotified,
-            isKeywordMatch = isKeywordMatch
+ isKeywordMatch = isKeywordMatch,
+ isFavorite = isFavorite
         )
     }
 
@@ -58,7 +60,8 @@ data class HotDealEntity(
                 mallUrl = domain.mallUrl,
                 createdAt = domain.createdAt,
  isNotified = domain.isNotified,
-                isKeywordMatch = domain.isKeywordMatch
+ isKeywordMatch = domain.isKeywordMatch,
+ isFavorite = domain.isFavorite
             )
         }
     }

app/src/main/java/com/hotdeal/alarm/di/DatabaseModule.kt

@@ -33,7 +33,8 @@ object DatabaseModule {
         )
  .addMigrations(
  AppDatabase.MIGRATION_1_2,
-                AppDatabase.MIGRATION_2_3
+ AppDatabase.MIGRATION_2_3,
+ AppDatabase.MIGRATION_3_4
  )
             .fallbackToDestructiveMigration()
             .build()

app/src/main/java/com/hotdeal/alarm/domain/model/HotDeal.kt

@@ -12,7 +12,8 @@ data class HotDeal(
     val mallUrl: String? = null, // 쇼핑몰 URL (추출된 경우)
  val createdAt: Long, // 수집 시간 (timestamp)
  val isNotified: Boolean = false,
-    val isKeywordMatch: Boolean = false
+ val isKeywordMatch: Boolean = false,
+ val isFavorite: Boolean = false // 즐겨찾기 여부
 ) {
     /**
      * 사이트 타입 반환