对齐币本位期权：现货缓冲开仓、页头 ETH/BTC 余额与默认 coin 模式。

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

lib/options/options_pricing_lib.py

@@ -512,12 +512,25 @@ def equivalent_contract_leverage(
     index_px: float | None,
     eth_amount: float | None,
     total_premium: float | None,
+    margin_mode: str | None = None,
 ) -> float | None:
-    """名义价值 / 权利金,近似相当于永续合约杠杆倍数(测算用)."""
+    """名义价值 / 权利金,近似相当于永续合约杠杆倍数(测算用).
+
+    USDC: 权利金为美元 → index×eth/premium.
+    币本位: 权利金为币 → eth/premium(=1/ask 当 premium=ask×eth).
+    """
     if index_px is None or eth_amount is None or total_premium is None:
         return None
     if eth_amount <= 0 or total_premium <= 0:
         return None
+    try:
+        from lib.options.options_margin_mode_lib import normalize_options_margin_mode
+
+        mode = normalize_options_margin_mode(margin_mode)
+    except Exception:
+        mode = (str(margin_mode or "usdc").strip().lower() or "usdc")
+    if mode == "coin":
+        return round(float(eth_amount) / float(total_premium), 1)
     return round(float(index_px) * float(eth_amount) / float(total_premium), 1)