fix卖回VWAP必须落库并覆盖指数占位价，禁止预算反推开仓价。

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

lib/options/options_coin_open_lib.py

@@ -511,6 +511,16 @@ def open_coin_option_buy_full(
         except Exception:
             pass
 
+        # 开仓价必须在缩减 coin_bought 之前按买币 VWAP 冻住
+        # (buy_usdt_spent/buy_coin_accum;禁止事后 budget/缩水权利金量反推)
+        open_px_freeze = idx_open
+        try:
+            bv = _spot_bridge.bridge_buy_vwap(conn, bridge_id)
+            if bv is not None and float(bv) > 0:
+                open_px_freeze = float(bv)
+        except Exception:
+            pass
+
         _spot_bridge.update_bridge(
             conn,
             bridge_id,
@@ -520,14 +530,6 @@ def open_coin_option_buy_full(
             message="期权持仓中",
         )
 
-        # 开仓价一次冻结:优先买币 VWAP(之后不再改);权利金币量 premium_paid 固定
-        open_px_freeze = idx_open
-        try:
-            bv = _spot_bridge.bridge_buy_vwap(conn, bridge_id)
-            if bv is not None and float(bv) > 0:
-                open_px_freeze = float(bv)
-        except Exception:
-            pass
         trade_id = _insert_coin_trade(
             conn,
             inst_id=inst_id,