feat(execution): AccountOrderWorker로 매수·매도 주문 직렬화

전략별 tick/scan 매도 락 대신 계좌 단일 PriorityQueue로 place를 B-full 직렬화한다.
틱매도 only_code 필터와 inflight 중복 enqueue 방지로 REST 폭주를 줄인다.

Co-authored-by: Cursor <cursoragent@cursor.com>

kis_trader/strategies/tail_catch.py

@@ -459,7 +459,7 @@ class TailCatchStrategy(BaseStrategy):
     # ------------------------------------------------------------------
     # 매도
     # ------------------------------------------------------------------
-    def check_sell_signals(self) -> List[Dict]:
+    def check_sell_signals(self, only_code: Optional[str] = None) -> List[Dict]:
         if not self.holdings or te is None:
             return []
 
@@ -477,6 +477,8 @@ class TailCatchStrategy(BaseStrategy):
 
         signals: List[Dict] = []
         for code, holding in list(self.holdings.items()):
+            if only_code and code != only_code:
+                continue
             try:
                 name = holding.get("name", code)
                 buy_price = float(holding.get("buy_price", 0))