feat: Add car availability check feature

- Add daily scheduled check for Carmodoo car availability
- Add manual trigger button in admin settings
- Mark sold cars as soldout=True automatically
- Add settings for check time and enable/disable toggle
- Display check status and statistics in admin UI

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/app/main.py

@@ -13,6 +13,7 @@ from .api import cars, auth, inquiries, hero_banners, carmodoo, translations, cc
 from .config import get_settings
 from .services.exchange_rate_service import update_exchange_rates
 from .services.visitor_service import aggregate_daily_stats, cleanup_old_visitor_logs
+from .services.car_availability_service import run_car_availability_check
 from datetime import datetime, timedelta
 
 app_settings = get_settings()
@@ -103,6 +104,19 @@ async def scheduled_cleanup_old_visitor_logs():
         db.close()
 
 
+async def scheduled_car_availability_check():
+    """Check car availability on Carmodoo"""
+    print("[Scheduler] Starting car availability check...")
+    db = SessionLocal()
+    try:
+        result = await run_car_availability_check(db)
+        print(f"[Scheduler] Car availability check completed: {result}")
+    except Exception as e:
+        print(f"[Scheduler] Car availability check failed: {e}")
+    finally:
+        db.close()
+
+
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     """앱 시작/종료 시 실행되는 lifespan 이벤트"""
@@ -136,8 +150,28 @@ async def lifespan(app: FastAPI):
         replace_existing=True
     )
 
+    # 차량 판매상태 검증 (매일 새벽 6시 - 설정에서 변경 가능)
+    # 동적 시간 설정을 위해 settings 확인
+    db = SessionLocal()
+    try:
+        from .models.settings import SystemSettings
+        settings = db.query(SystemSettings).first()
+        check_hour = settings.car_availability_check_hour if settings else 6
+    except:
+        check_hour = 6
+    finally:
+        db.close()
+
+    scheduler.add_job(
+        scheduled_car_availability_check,
+        CronTrigger(hour=check_hour, minute=0),
+        id="daily_car_availability_check",
+        name="Daily Car Availability Check",
+        replace_existing=True
+    )
+
     scheduler.start()
-    print("[Startup] Scheduler started - Exchange rates: 11:30 AM, Visitor stats: 2:00 AM, Log cleanup: Sunday 3:00 AM")
+    print(f"[Startup] Scheduler started - Exchange rates: 11:30 AM, Visitor stats: 2:00 AM, Log cleanup: Sunday 3:00 AM, Car availability: {check_hour}:00 AM")
 
     # 서버 시작 시 환율 데이터 초기화 (백그라운드에서)
     asyncio.create_task(scheduled_update_exchange_rates())