refactor: redesign order flow - serve first, pay later

- Redesign order status flow: 0待接单→1已接单→2服务中→3待支付→4已完成
- Allow service start from status 1 (removed payment barrier)
- Add payment entry after service completion (status 3)
- Update Android/miniprogram UI status mappings
- Add order flow design document to docs/

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

coupon/app.js

@@ -1,4 +1,6 @@
 // app.js
+const config = require('./utils/config')
+
 App({
   onLaunch() {
     const uid = wx.getStorageSync('uid')
@@ -16,9 +18,10 @@ App({
     iv: '',
     code: '',
 
-  
   //  url: 'https://ruilaizipj.com',
-    url: 'http://101.43.95.130:8039',
+    url: config.baseUrl,
+    domain: config.baseUrl,
+    domaintwo: config.baseUrl,