── 取值来源（不含密钥值）──
  base-url = https://test.gdyfsk.com/yfpay   [application.yml 字面量]
  inst-no  = 900112             [application.yml 默认值（键 LESHOUYING_INST_NO）]
  key      = <len=32>        [application.yml 默认值（键 LESHOUYING_KEY）]

── 将发送（不含密钥；sign 打码）──
  A = inst_no=900112&mch_no=Y52211090004&order_body=联调探针-H5&pay_time=20260928160450&pay_trace_no=probe20260928160450h5&pay_type=300&total_amount=1

  body = {
  "inst_no": "900112",
  "mch_no": "Y52211090004",
  "pay_type": "300",
  "pay_trace_no": "probe20260928160450h5",
  "pay_time": "20260928160450",
  "total_amount": "1",
  "order_body": "联调探针-H5",
  "sign": "<len=32>"
}

  字段清单（= 生产 createH5Order 发的集合）：inst_no, mch_no, order_body, pay_time, pay_trace_no, pay_type, sign, total_amount

── 出站 ──
  POST https://test.gdyfsk.com/yfpay/v3/h5pay
  Content-Type: application/json;charset=utf-8
  bytes = 235

── 上游应答 ──
  http_code = 200
  bytes     = 785
  原始字节已落 logs/_lsy-h5pay-resp.bin

  解码 = utf-8 成功
  ali_trade_no     = null
  appId            = null
  attach           = null
  code_url         = 'https://yyfweb.postar.cn/postalpay/p/generateCode/cloud?threeOrderNo=200001070X4326092816045010002&agetId=FWH000012501&orderDate=20260928'
  coupon_amount    = null
  discount_amount  = null
  mch_name         = '建行小店基本休息修改'
  mch_no           = 'Y52211090004'
  mem_data         = null
  miniapp_data     = null
  nonceStr         = null
  packages         = null
  paySign          = null
  pay_amount       = null
  pay_time         = '20260928160450'
  pay_trace_no     = 'probe20260928160450h5'
  pay_type         = '300'
  receipt_amount   = null
  result_code      = 'PAY_SUCCESS'
  return_code      = 'SUCCESS'
  return_msg       = '预支付成功'
  shop_name        = ''
  shop_no          = ''
  sign             = '261c9e764f3cb8d59a67b486acd2d629'
  signType         = null
  timeStamp        = null
  total_amount     = '1'
  trade_no         = '200001070X4326092816045010002'
  trade_state      = null

── 入站验签（null 不参与）──
  参与签名的字段数 = 13 / 应答字段数 28
  A = code_url=https://yyfweb.postar.cn/postalpay/p/generateCode/cloud?threeOrderNo=200001070X4326092816045010002&agetId=FWH000012501&orderDate=20260928&mch_name=建行小店基本休息修改&mch_no=Y52211090004&pay_time=20260928160450&pay_trace_no=probe20260928160450h5&pay_type=300&result_code=PAY_SUCCESS&return_code=SUCCESS&return_msg=预支付成功&shop_name=&shop_no=&total_amount=1&trade_no=200001070X4326092816045010002
  重算 == 上游 sign : True

── 判读线索（脚本不下结论）──
  return_code = SUCCESS
  return_msg  = 预支付成功
  result_code = PAY_SUCCESS