Fix trades API 500 by supporting sqlite Row in hold timing.

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

backend/tests/test_hold_timing.py

@@ -55,9 +55,32 @@ def test_hold_dual_leg_uses_group_close():
     assert h["hold_basis"] == "group"
 
 
-def test_hold_open_no_close():
-    g = {"open_at_ms": 100, "close_at_ms": None, "status": "open", "close_reason": None}
-    h = hold_timing(g, [])
-    assert h["hold_close_at_ms"] is None
-    assert h["hold_ms"] is None
-    assert h["hold_basis"] == "open"
+def test_hold_sqlite_row_like_without_get():
+    """sqlite3.Row 无 .get，需能转 dict。"""
+
+    class Row:
+        def __init__(self, d):
+            self._d = d
+
+        def keys(self):
+            return self._d.keys()
+
+        def __getitem__(self, k):
+            return self._d[k]
+
+        def __iter__(self):
+            return iter(self._d)
+
+    g = Row(
+        {
+            "open_at_ms": 100,
+            "close_at_ms": None,
+            "status": "option_residual",
+            "close_reason": "target_perp_only",
+        }
+    )
+    fills = [Row({"leg": "perp", "action": "close", "ts_ms": 400})]
+    h = hold_timing(g, fills)
+    assert h["hold_close_at_ms"] == 400
+    assert h["hold_ms"] == 300
+