feat: 연차 관리 기능 추가 (AnnualLeave 엔티티, DAO, Repository)

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

app/src/main/java/com/example/shiftalarm/AppDatabase.kt

@@ -3,7 +3,7 @@ package com.example.shiftalarm
 import android.content.Context
 import androidx.room.*
 
-@Database(entities = [ShiftOverride::class, DailyMemo::class, CustomAlarm::class], version = 3, exportSchema = false)
+@Database(entities = [ShiftOverride::class, DailyMemo::class, CustomAlarm::class, AnnualLeave::class], version = 4, exportSchema = false)
 abstract class AppDatabase : RoomDatabase() {
     abstract fun shiftDao(): ShiftDao
 

app/src/main/java/com/example/shiftalarm/Entities.kt

@@ -1,6 +1,7 @@
 package com.example.shiftalarm
 
-import androidx.room.*
+import androidx.room.Entity
+import androidx.room.PrimaryKey
 
 @Entity(tableName = "shift_overrides", primaryKeys = ["factory", "team", "date"])
 data class ShiftOverride(
@@ -28,3 +29,12 @@ data class CustomAlarm(
     val snoozeInterval: Int = 5,
     val snoozeRepeat: Int = 3
 )
+
+@Entity(tableName = "annual_leave")
+data class AnnualLeave(
+    @PrimaryKey
+    val id: Int = 1, // Single row for app-wide annual leave
+    val totalDays: Float, // 총 연차 (1~25)
+    val remainingDays: Float, // 남은 연차
+    val updatedAt: Long = System.currentTimeMillis()
+)

app/src/main/java/com/example/shiftalarm/ShiftDao.kt

@@ -1,6 +1,11 @@
 package com.example.shiftalarm
 
-import androidx.room.*
+import androidx.room.Dao
+import androidx.room.Delete
+import androidx.room.Insert
+import androidx.room.OnConflictStrategy
+import androidx.room.Query
+import androidx.room.Update
 
 @Dao
 interface ShiftDao {
@@ -57,4 +62,17 @@ interface ShiftDao {
 
     @Query("DELETE FROM custom_alarms")
     suspend fun clearCustomAlarms()
+
+    // Annual Leave Queries
+    @Query("SELECT * FROM annual_leave WHERE id = 1")
+    suspend fun getAnnualLeave(): AnnualLeave?
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    suspend fun insertAnnualLeave(annualLeave: AnnualLeave)
+
+    @Query("UPDATE annual_leave SET remainingDays = :remainingDays, updatedAt = :timestamp WHERE id = 1")
+    suspend fun updateRemainingDays(remainingDays: Float, timestamp: Long = System.currentTimeMillis())
+
+    @Query("DELETE FROM annual_leave")
+    suspend fun clearAnnualLeave()
 }

app/src/main/java/com/example/shiftalarm/ShiftRepository.kt

@@ -57,4 +57,47 @@ class ShiftRepository(private val context: Context) {
     suspend fun clearAllCustomAlarms() = withContext(Dispatchers.IO) {
         dao.clearCustomAlarms()
     }
+
+    // Annual Leave
+    suspend fun calculateUsedAnnualLeave(): Float = withContext(Dispatchers.IO) {
+        val currentYear = java.time.Year.now().toString()
+        val overrides = dao.getAllOverrides()
+        
+        var usedDays = 0f
+        
+        for (override in overrides) {
+            if (override.date.startsWith(currentYear)) {
+                when (override.shift) {
+                    "연차" -> usedDays += 1f
+                    "반년" -> usedDays += 0.5f
+                }
+            }
+        }
+        
+        usedDays
+    }
+
+    suspend fun getAnnualLeave(): AnnualLeave? = withContext(Dispatchers.IO) {
+        dao.getAnnualLeave()
+    }
+
+    suspend fun recalculateAndSaveAnnualLeave(totalDays: Float) {
+        val usedDays = calculateUsedAnnualLeave()
+        val remainingDays = totalDays - usedDays
+        
+        dao.insertAnnualLeave(AnnualLeave(
+            id = 1,
+            totalDays = totalDays,
+            remainingDays = remainingDays
+        ))
+    }
+
+    suspend fun updateRemainingAnnualLeave() {
+        val annualLeave = dao.getAnnualLeave()
+        annualLeave?.let {
+            val usedDays = calculateUsedAnnualLeave()
+            val remainingDays = it.totalDays - usedDays
+            dao.insertAnnualLeave(it.copy(remainingDays = remainingDays))
+        }
+    }
 }