Add fixed-direction switch for perp/option open side.

When enabled, lock perp long→buy Put or short→buy Call with ITM/ATM only; off keeps ATM/ask rules.

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

backend/app/config.py

@@ -72,6 +72,9 @@ class Settings(BaseSettings):
     min_option_leverage: float = 100.0  # 现价/卖一权利金 下限
     atm_open_offset_enabled: bool = False  # 开仓 ATM 偏差限制开关（默认关）
     max_atm_open_offset: float = 3.0  # 开启后：|ATM行权价−标的| 上限（点）
+    # 固定方向：关=现有 ATM/比价规则；开=指定永续多/空，期权 Put/Call 且须实值或平值
+    fixed_direction_enabled: bool = False
+    fixed_perp_side: str = "long"  # long|short；long→买Put，short→买Call
     close_bid_mark_max_pct: float = 30.0  # 平仓：买一相对标记最大偏差%
     perp_qty_eth: float = 1.0
     option_qty_eth: float = 2.0