Prefer open direction from ATM vs spot (below=Call/short, above=Put/long).

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

backend/app/exchange/types.py

@@ -76,19 +76,38 @@ class MarketSnapshot:
             "ask_compare": {
                 "call_ask": self.call.ask if self.call else None,
                 "put_ask": self.put.ask if self.put else None,
-                "bias": _ask_bias(self.call, self.put),
+                "bias": _open_bias(self.pair, self.index_px, self.perp, self.call, self.put),
             },
         }
 
 
-def _ask_bias(call: Quote | None, put: Quote | None) -> str:
-    """卖一比价仅用于选向展示；相等则 wait。"""
+def _open_bias(
+    pair: OptionPair | None,
+    index_px: float | None,
+    perp: Quote | None,
+    call: Quote | None,
+    put: Quote | None,
+) -> str:
+    """与开仓 decide 一致：先按 ATM 相对现价，贴平时再卖一比价。"""
+    mark = None
+    if index_px is not None and index_px > 0:
+        mark = float(index_px)
+    elif perp and perp.mark_px and perp.mark_px > 0:
+        mark = float(perp.mark_px)
+    elif perp and perp.bid and perp.ask:
+        mark = (float(perp.bid) + float(perp.ask)) / 2
+    if pair is not None and mark is not None:
+        diff = float(pair.strike) - mark
+        if diff < -1e-9:
+            return "strike_below_spot"
+        if diff > 1e-9:
+            return "strike_above_spot"
     ca = call.ask if call else None
     pa = put.ask if put else None
     if ca is None or pa is None:
         return "unknown"
     if ca > pa:
-        return "call_ask_gt_put"  # 永续多 + 期权空（腿待拍板）
+        return "call_ask_gt_put"
     if ca < pa:
-        return "put_ask_gt_call"  # 永续空 + 期权多（腿待拍板）
+        return "put_ask_gt_call"
     return "equal"