날짜 수정

backend/app/services/mdd_manager.py

@@ -7,7 +7,7 @@ MDD(Maximum Drawdown) 관리 - CLAUDE.md 섹션 6.3
 """
 import asyncio
 import logging
-from typing import Dict
+from typing import Dict, Optional
 
 logger = logging.getLogger(__name__)
 
@@ -18,7 +18,7 @@ class MDDManager:
     def __init__(self):
         self.peak_balance: float = 0.0
         self.is_paused: bool = False
-        self.reduction_applied: str = None  # None, "10pct", "20pct"
+        self.reduction_applied: Optional[str] = None  # None, "10pct", "20pct"
         self._lock = asyncio.Lock()  # 스케줄러-sync 동시 접근 방지
 
     async def update(self, current_balance: float) -> Dict: