Try all OTM strikes in offset when nearest fails leverage.

Closest Call@1920 at 152x no longer blocks 1930/1940 that already clear 200x.

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

backend/app/strategy/selection.py

@@ -46,18 +46,19 @@ def pick_atm_strike(strikes: list[float], mark_px: float) -> float | None:
     return min(strikes, key=lambda s: (abs(s - mark_px), s))
 
 
-def pick_otm_strike(
+def list_otm_strikes(
     strikes: list[float],
     mark_px: float,
     *,
     option_side: str,
     max_offset: float,
-) -> float | None:
+) -> list[float]:
     """
-    虚值：Call K>S、Put K<S；取最接近标的且 |K−S|≤max_offset 的一档。
+    虚值候选：Call K>S、Put K<S 且 |K−S|≤max_offset；
+    按靠近标的优先排序（近→远）。
     """
     if not strikes or mark_px <= 0:
-        return None
+        return []
     side = (option_side or "").strip().lower()
     spot = float(mark_px)
     cap = max(0.0, float(max_offset))
@@ -74,10 +75,25 @@ def pick_otm_strike(
             if float(s) < spot - 1e-9 and spot - float(s) <= cap + 1e-9
         ]
     else:
-        return None
-    if not cands:
-        return None
-    return min(cands, key=lambda s: (abs(s - spot), s))
+        return []
+    return sorted(cands, key=lambda s: (abs(s - spot), s))
+
+
+def pick_otm_strike(
+    strikes: list[float],
+    mark_px: float,
+    *,
+    option_side: str,
+    max_offset: float,
+) -> float | None:
+    """虚值：取最接近标的且 |K−S|≤max_offset 的一档。"""
+    cands = list_otm_strikes(
+        strikes,
+        mark_px,
+        option_side=option_side,
+        max_offset=max_offset,
+    )
+    return cands[0] if cands else None
 
 
 def is_otm(*, option_side: str, strike: float, mark_px: float) -> bool: