距平衡改为行权价到平衡价的价差

Call 为 BE−K、Put 为 K−BE；链/下单/持仓统一；顺带修复 format_position_row 中 row_mode 引用顺序。

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

tests/test_options_pricing.py

@@ -349,6 +349,13 @@ def test_expiry_breakeven_coin_margin():
     ) == round(2425 / (1 - 0.0187), 2)
 
 
+def test_strike_distance_to_be():
+    from lib.options.options_pricing_lib import strike_distance_to_be
+
+    assert strike_distance_to_be(2390, 2430, opt_type="C") == 40.0
+    assert strike_distance_to_be(2450, 2411, opt_type="P") == 39.0
+
+
 def test_straddle_breakeven_band_coin():
     from lib.options.options_pricing_lib import straddle_breakeven_band
 
@@ -454,4 +461,4 @@ def test_format_position_row_breakeven():
     assert row["expiry_be_px"] == 3515.6
     assert row["idx_px"] == 3480.0
     assert row["close_be_px"] is not None
-    assert row["dist_expiry_be"] == 35.6
+    assert row["dist_expiry_be"] == 15.6