refactor: 移除 ScanStruct 中 time.Time 直接存储的特殊处理，同步更新测试精度预期

exec/scanner.go

@@ -198,14 +198,8 @@ func (s *scanner) ScanStruct(i interface{}) error {
 	record := map[string]interface{}{}
 	for index, col := range s.columns {
 		if pi, ok := scans[index].(*interface{}); ok {
-			v := *pi
-			if t, isTime := v.(time.Time); isTime {
-				// time.Time 直接存储，避免格式化字符串丢失纳秒和时区
-				record[col] = t
-			} else {
-				raw := toJSONRawMessage(v)
-				record[col] = &raw
-			}
+			raw := toJSONRawMessage(*pi)
+			record[col] = &raw
 		} else {
 			record[col] = scans[index]
 		}