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

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

backend/app/strategy/exits.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import time
 from dataclasses import dataclass
 
 EXIT_MODE_FIXED = "fixed_usdt"
@@ -28,6 +29,20 @@ def resolve_exit_target(
     return float(net_profit_target), EXIT_MODE_FIXED
 
 
+def check_expiry_close(
+    *,
+    expiry_ms: int | None,
+    now_ms: int | None = None,
+) -> ExitDecision:
+    """期权到期时刻（含）→ 强制全平。"""
+    if expiry_ms is None:
+        return ExitDecision(False, "", 0.0)
+    now = int(time.time() * 1000) if now_ms is None else int(now_ms)
+    if now >= int(expiry_ms):
+        return ExitDecision(True, "expiry", 0.0)
+    return ExitDecision(False, "", 0.0)
+
+
 def check_exits(
     *,
     net_pnl: float,