Fix OO expiry settle index: persist spot and never invent strike from OTM fill.

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

backend/app/api/trades.py

@@ -25,6 +25,7 @@ def _is_oo_group(g: dict) -> bool:
 
 
 def _infer_settle_index(g: dict, fills: list) -> float | None:
+    """优先库内 settle_index_px；否则用「实值腿」成交反推。虚值 fill≈0 时禁止推成行权价。"""
     settle_index = g.get("settle_index_px")
     if settle_index is not None:
         try:
@@ -33,25 +34,44 @@ def _infer_settle_index(g: dict, fills: list) -> float | None:
                 return v
         except (TypeError, ValueError):
             pass
-    strike = g.get("strike")
-    side = str(g.get("option_side") or "").lower()
-    if strike is None:
-        return None
+
+    candidates: list[float] = []
     for raw in fills:
         f = dict(raw) if not isinstance(raw, dict) else raw
-        if str(f.get("leg")) != "option" or str(f.get("action")) != "close":
+        if str(f.get("action") or "") != "close":
+            continue
+        leg = str(f.get("leg") or "")
+        if leg not in ("option", "option2"):
             continue
         if abs(float(f.get("slip") or 0)) > 1e-12:
             continue
-        px = float(f.get("fill_px") or 0)
-        k = float(strike)
+        try:
+            px = float(f.get("fill_px") or 0)
+        except (TypeError, ValueError):
+            continue
+        # 虚值到期 fill=0：k+0 / k-0 会得到行权价，不是真实结算指数
+        if px <= 1e-9:
+            continue
+        if leg == "option":
+            strike = g.get("strike")
+            side = str(g.get("option_side") or "").lower()
+        else:
+            strike = g.get("strike2")
+            side = str(g.get("option2_side") or "put").lower()
+        if strike is None:
+            continue
+        try:
+            k = float(strike)
+        except (TypeError, ValueError):
+            continue
         if side in ("call", "c"):
-            return k + px
-        if side in ("put", "p"):
-            return k - px
-        break
-    return None
-
+            candidates.append(k + px)
+        elif side in ("put", "p"):
+            candidates.append(k - px)
+    if not candidates:
+        return None
+    # 多腿一致时取平均；实值腿通常只有一条
+    return round(sum(candidates) / len(candidates), 4)
 
 def _intrinsic(side: str, settle_index: float, strike: float) -> float:
     s = str(side or "").lower()
@@ -112,7 +132,7 @@ def _expiry_settle_info(g: dict, fills: list) -> dict | None:
 
 
 def _close_index_px(g: dict, fills: list) -> float | None:
-    """平仓时标的指数：优先 settle_index_px，否则用永续平仓价近似。"""
+    """平仓时标的指数：优先库内 settle；到期才用实值腿反推；否则永续平仓价。"""
     raw = g.get("settle_index_px")
     if raw is not None:
         try:
@@ -121,6 +141,11 @@ def _close_index_px(g: dict, fills: list) -> float | None:
                 return v
         except (TypeError, ValueError):
             pass
+    # 仅到期：期权平仓价=内在价值，可反推指数；中途卖出的权利金不能当指数
+    if str(g.get("close_reason") or "") == "expiry":
+        inferred = _infer_settle_index(g, fills)
+        if inferred is not None and inferred > 0:
+            return inferred
     for row in fills:
         f = dict(row) if not isinstance(row, dict) else row
         if str(f.get("leg") or "") == "perp" and str(f.get("action") or "") == "close":