Add weekend open skip, expiry force-close, and Chinese trade labels.

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

backend/app/strategy/clock.py

@@ -1,4 +1,4 @@
-"""日历日分组键（开仓时间窗已取消，由期权剩余时长约束）。"""
+"""日历日分组键；可选周末跳过开仓（上海时区）。"""
 
 from __future__ import annotations
 
@@ -17,13 +17,22 @@ def window_key(now: datetime | None = None) -> str:
     return now_sh(now).strftime("%Y%m%d")
 
 
+def is_weekend(now: datetime | None = None) -> bool:
+    """上海时区：周六=5、周日=6。"""
+    return now_sh(now).weekday() >= 5
+
+
 def can_open_new(
     now: datetime | None = None,
     *,
+    skip_weekends: bool = True,
     open_hhmm: str = "16:00",
     stop_hhmm: str = "08:00",
 ) -> bool:
-    """开仓窗已取消，始终允许（仍受期权剩余时长/杠杆筛选）。"""
+    """是否允许新开仓。开仓窗已取消；可选跳过周六日。持仓平仓不受此限制。"""
+    _ = open_hhmm, stop_hhmm
+    if skip_weekends and is_weekend(now):
+        return False
     return True