Add martingale mode for risk-based percent sizing.

Enable in settings (default off): after N consecutive loss days, double the effective risk_loss_pct up to a configurable max; blocked when base pct > 3%.

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

backend/app/config.py

@@ -76,6 +76,10 @@ class Settings(BaseSettings):
     min_option_leverage: float = 100.0  # 现价/卖一权利金 下限
     # 以损定仓权利金口径：actual=盘口卖一；selection=指数/选约杠杆（控节奏，默认）
     risk_leverage_basis: str = "selection"
+    # 倍投：默认关；仅以损定仓+亏损幅度%且基础幅度≤3% 可开
+    martingale_enabled: bool = False
+    martingale_start_after_loss_days: int = 2  # 连续亏损 N 天后开始翻倍
+    martingale_max_doubles: int = 3  # 最多翻倍次数（如 2→4→8→16 为 3 次）
     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