feat(order): wappay/index 越南地区追加 USDT(Epay) 支付选项

- Order::wappay/index: area_id=3 时合并 pay_list['epay']['type'] 到 payMethod，
  每个选项带 pay_routes 映射到对应 online_order_fac
- wappay.html: select 的 option 加 data-url，JS 按选中项查路由
- 兼容旧行为：未设置 pay_routes 时 fallback 到原 online_order_fac

application/onlinechip/view/order/wappay.html

@@ -204,7 +204,7 @@
 		<i class="icon"></i>
 		<select class="select" name="pay_type" id="pay_type">
 			<?php foreach($payMethod as $key=>$method): ?>
-			<option value ="<?=$key?>"><?=$method?></option>
+			<option value ="<?=$key?>" data-url="/order/<?=isset($pay_routes[$key])?$pay_routes[$key]:$online_order_fac?>"><?=$method?></option>
 			<?php endForeach; ?>
 		</select>
 	</div>
@@ -233,7 +233,8 @@
 					query.price = price;
 					query.username = username;
 					query.pay_type = pay_type;
-					url = '/order/<?=$online_order_fac ?>';
+					// 每种支付方式对应的 online_order 路由可能不同
+					url = $('#pay_type option:selected').data('url') || '/order/<?=$online_order_fac ?>';
 					//var winRef = window.open("","_blank");
 					$.ajax({
 						url:url,