fix(pay): 待支付浮窗无刷新同步

- modal-cache 失效时广播 aksrt:cache:invalidated
- 新增 GET /orders/wait-pay-float 返回浮窗片段
- wait-pay-float.js 监听 orders 标签失效并替换/移除浮窗、重启倒计时
- VIP/充值/下载待支付分支触发 orders 失效

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

src/Payment/OrderCenterRest.php

@@ -40,6 +40,12 @@ class OrderCenterRest {
             'permission_callback' => [$this, 'require_logged_in'],
             'args' => $query_args,
         ]);
+        // 待支付浮窗片段：须在 /orders/{order_number} 之前注册，避免被单号路由吞掉。
+        register_rest_route($namespace, '/orders/wait-pay-float', [
+            'methods' => \WP_REST_Server::READABLE,
+            'callback' => [$this, 'get_wait_pay_float'],
+            'permission_callback' => [$this, 'require_logged_in'],
+        ]);
         $route_args = [
             'order_number' => [
                 'required' => true,
@@ -97,6 +103,15 @@ class OrderCenterRest {
         return $this->success(['data' => $view]);
     }
 
+    public function get_wait_pay_float(): \WP_REST_Response {
+        $enabled = class_exists('\AKSRT\Settings\Settings')
+            && !empty(\AKSRT\Settings\Settings::get_order_settings()['wait_float']);
+        $html = $enabled && function_exists('aksrt_get_wait_pay_float_html') ? aksrt_get_wait_pay_float_html() : '';
+        $response = $this->success(['data' => ['html' => $html]]);
+        $response->header('Cache-Control', 'no-store, private');
+        return $response;
+    }
+
     public function pay(\WP_REST_Request $request): \WP_REST_Response {
 		$operation_key = \AKSRT\Ledger\OperationKey::from_request($request, 'order-pay', get_current_user_id());
 		if (is_wp_error($operation_key)) {