Add one-expiry-per-day open rhythm gate (default on).

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

backend/app/api/settings.py

@@ -35,6 +35,7 @@ KEYS = (
     "rest_seconds",
     "live_order_interval_sec",
     "skip_weekends",
+    "one_expiry_per_day",
     "initial_equity",
     "leverage",
     "perp_margin_mode",
@@ -69,6 +70,7 @@ class StrategySettingsBody(BaseModel):
     rest_seconds: int | None = Field(default=None, ge=0, le=3600)
     live_order_interval_sec: float | None = Field(default=None, ge=0.2, le=30)
     skip_weekends: bool | None = None
+    one_expiry_per_day: bool | None = None
     initial_equity: float | None = Field(default=None, ge=1000, le=10_000_000)
     leverage: float | None = Field(default=None, ge=1, le=125)
     perp_margin_mode: str | None = Field(default=None, pattern="^(cross|isolated)$")
@@ -144,6 +146,10 @@ def _read_settings() -> dict:
         "skip_weekends": _as_bool(
             db.get_setting("skip_weekends", str(s.skip_weekends)), s.skip_weekends
         ),
+        "one_expiry_per_day": _as_bool(
+            db.get_setting("one_expiry_per_day", str(s.one_expiry_per_day)),
+            s.one_expiry_per_day,
+        ),
         "initial_equity": float(
             db.get_setting("initial_equity", str(s.initial_equity)) or s.initial_equity
         ),