feat(pay): 统一收银台四种模式（站内二维码/当前页跳转/表单提交/JSAPI）

- PaymentOrchestrator 统一返回 mode + code_url/payment_url/form_html/jsapi_params
- 支付宝：当面付二维码 / 电脑网站支付 / H5；微信：Native / H5 / JSAPI（WechatOpenid 静默授权）
- 易支付：PC mapi 二维码，移动端自动提交表单
- 删除旧键 alipay_payment_type / wechat_payment_type / epay_device 与 redirect/qr_content 字段
- 新增 pay-cashier.js，移除 window.open，订单状态接口改为 /pay/order/{n}
- 拆分 credits.js（affiliate / withdraw-history）至 1000 行以内

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

assets/js/vip-purchase-coordinator.js

@@ -10,7 +10,7 @@
 (function (window, document) {
   "use strict";
 
-  var ORDER_PATH = "/pay/content/order/";
+  var ORDER_PATH = "/pay/order/";
   var DEFAULT_MAX_ATTEMPTS = 12;
   var DEFAULT_MAX_ELAPSED = 120000;
   var MAX_DELAY = 15000;
@@ -374,7 +374,7 @@
         callback(options, "onError", response);
         return response;
       }
-      if (data.redirect && (data.payment_url || data.qr_content)) {
+      if (data.mode) {
         invalidate(["orders"]);
         callback(options, "onPending", data);
         if (!data.order_number) {