feat(M08-B): 接入保洁微信转账适配器

backend/tests/wechat-pay.test.mjs

@@ -29,7 +29,13 @@ const responses = [
   { prepay_id: 'wx-prepay-test' },
   { trade_state: 'SUCCESS', transaction_id: 'wx-transaction-test' },
   { refund_id: 'wx-refund-test', status: 'PROCESSING' },
-  { download_url: 'https://api.mch.weixin.qq.com/v3/billdownload/file?token=sanitized' }
+  { download_url: 'https://api.mch.weixin.qq.com/v3/billdownload/file?token=sanitized' },
+  {
+    out_bill_no: 'CLP501',
+    transfer_bill_no: 'wx-transfer-501',
+    state: 'WAIT_USER_CONFIRM',
+    package_info: 'package-info'
+  }
 ];
 const transport = {
   async request(input) {
@@ -73,6 +79,21 @@ assert.match((await client.downloadTradeBill(
   credential, '2026-06-21', 'ALL'
 )).download_url, /^https:/);
 
+const transfer = await client.createMerchantTransfer(credential, {
+  outBillNo: 'CLP501',
+  openid: 'openid-sanitized',
+  amountCents: 800,
+  remark: '保洁结算501',
+  sceneId: '1000',
+  reportInfos: [{ infoType: '岗位类型', infoContent: '保洁员' }]
+});
+assert.equal(transfer.state, 'WAIT_USER_CONFIRM');
+assert.equal(transfer.packageInfo, 'package-info');
+assert.match(requests[4].url, /\/v3\/fund-app\/mch-transfer\/transfer-bills$/);
+assert.match(requests[4].body, /"out_bill_no":"CLP501"/);
+assert.match(requests[4].body, /"transfer_amount":800/);
+assert.equal(requests[4].headers.Authorization.includes(merchantKeys.privateKey), false);
+
 const notification = encryptedNotification({
   out_trade_no: 'PAY-M05B-001',
   transaction_id: 'wx-transaction-test',