feat(pay): content cashier, resource orders at VIP price, purchase/download JS loop

Wire zibll-style one-shot points/cash cashier for post+_aksrt_pay downloads:
server amount from aksrt_get_user_pay_price, ORDER_PRODUCT_RESOURCE unlock,
frontend need-purchase opens modal, download box purchased/VIP/purchase CTAs.

inc/classes/scripts-traits/trait-aksrt-scripts-part-1b.php

@@ -140,6 +140,24 @@ trait AKSRT_Scripts_Part_1b {
         $is_single_resource  = (function_exists('aksrt_is_resource_post') && is_singular() && aksrt_is_resource_post(get_queried_object_id()));
         // 普通博客 single（排除资源型 post）
         $is_single_post      = is_singular('post') && !$is_single_resource;
+        // 付费下载/付费墙：任意 singular 需收银台/下载脚本
+        $is_paid_content_single = false;
+        if (is_singular()) {
+            $qid = (int) get_queried_object_id();
+            if ($qid > 0) {
+                if (function_exists('aksrt_is_downloadable_content') && aksrt_is_downloadable_content($qid)) {
+                    $is_paid_content_single = true;
+                } elseif (function_exists('aksrt_is_paid_post') && aksrt_is_paid_post($qid)) {
+                    $is_paid_content_single = true;
+                } elseif (function_exists('aksrt_get_pay_meta')) {
+                    $pm = aksrt_get_pay_meta($qid);
+                    $pt = (string) ($pm['pay_type'] ?? 'no');
+                    $is_paid_content_single = ($pt !== '' && $pt !== 'no');
+                }
+            }
+        }
+        // 独立下载页模板
+        $is_download_file_page = is_page_template('templates/pages/page-download-file.php');
         // 资源虚拟列表 /resources/
         $is_resource_archive = function_exists('aksrt_is_resource_archive') && aksrt_is_resource_archive();
         // /user/{nicename}/ 自定义重写路由（class-aksrt-user.php 注册）
@@ -643,13 +661,13 @@ trait AKSRT_Scripts_Part_1b {
             $enqueue_module('resource-archive');
         }
 
-        // 单篇资源：下载脚本
-        if ($is_single_resource) {
+        // 单篇资源 / 付费内容 / 独立下载页：下载 + 收银台脚本
+        if ($is_single_resource || $is_paid_content_single || $is_download_file_page) {
             $cms_download_js_path = get_template_directory() . '/assets/js/cms-download.js';
             wp_enqueue_script(
                 'aksrt-cms-download',
                 $base_uri . '/assets/js/cms-download.js',
-                ['aksrt-script'],
+                ['aksrt-script', 'aksrt-runtime'],
                 file_exists($cms_download_js_path) ? (string) filemtime($cms_download_js_path) : $version,
                 true
             );