── 被查的那笔单（读自上一发的原始应答，非手抄）──
  pay_trace_no = probe20260928152114qr
  pay_time     = 20260928152114
  上一发是否给了 trade_no : False  （qrpay 返回表里本就没有这个字段）

── 将发送（不含密钥；sign 打码）──
{
  "inst_no": "900112",
  "mch_no": "Y52211090004",
  "query_trace_no": "ea811eb1179d442e928aae84a0423aaf",
  "pay_trace_no": "probe20260928152114qr",
  "pay_time": "20260928152114",
  "sign": "<len=32>"
}

── 出站 ──
  POST https://test.gdyfsk.com/yfpay/v3/queryorder
  bytes = 216

── 上游应答 ──
  http_code = 200, bytes = 481
{
  "return_code": "FAIL",
  "return_msg": "订单信息不存在！",
  "result_code": null,
  "pay_type": null,
  "mch_name": null,
  "shop_name": null,
  "mch_no": null,
  "shop_no": null,
  "query_trace_no": null,
  "pay_trace_no": null,
  "pay_time": null,
  "total_amount": null,
  "end_time": null,
  "trade_no": null,
  "td_trade_no": null,
  "qd_trade_no": null,
  "user_id": null,
  "attach": null,
  "trade_state": null,
  "receipt_amount": null,
  "pay_amount": null,
  "coupon_amount": null,
  "discount_amount": null,
  "sign": "a3cb8169d863e438486a6ea0ae72fea7"
}

── 入站验签（null 不参与）──
  参与签名字段数 = 2
  重算 == 上游 sign : True