feat(orders): embed My Orders inside user center (zibll-style)

Register UC panel tab=orders with full order list/actions UI; route
aksrt_get_orders_page_url and /orders template to profile?tab=orders;
enqueue order assets when the UC orders tab is active.

src/AKSRT/User/Center.php

@@ -71,6 +71,12 @@ class Center {
                 'priority' => 45,
                 'type'     => 'panel',
             ],
+            'orders' => [
+                'label'    => __('我的订单', 'aksrt'),
+                'icon'     => 'receipt',
+                'priority' => 48,
+                'type'     => 'panel',
+            ],
             'credits' => [
                 'label'    => class_exists('\AKSRT\Settings\Settings')
                     ? sprintf(__('我的%s', 'aksrt'), \AKSRT\Settings\Settings::get_currency_name())
@@ -104,7 +110,7 @@ class Center {
         $vip_on = class_exists('\AKSRT\Settings\Settings')
             && !empty(\AKSRT\Settings\Settings::get_payment_vip_settings()['enabled']);
 
-        // Follow configured order; always auto-include VIP/credits when feature on.
+        // Follow configured order; always auto-include VIP/orders/credits when feature on.
         $order = $configured;
         if ($vip_on && !in_array('vip', $order, true)) {
             $insert_at = count($order);
@@ -117,6 +123,24 @@ class Center {
             }
             array_splice($order, $insert_at, 0, ['vip']);
         }
+        // Orders panel: always available when payment/shop stack exists (UserOrders or Shop).
+        $orders_on = class_exists('\AKSRT\Payment\UserOrders')
+            || class_exists('\AKSRT\Payment\Order')
+            || class_exists('\AKSRT\Shop\Shop');
+        if ($orders_on && !in_array('orders', $order, true)) {
+            $insert_at = count($order);
+            foreach (['vip', 'credits', 'favorites'] as $anchor) {
+                $idx = array_search($anchor, $order, true);
+                if ($idx !== false) {
+                    $insert_at = (int) $idx + ($anchor === 'vip' ? 1 : 0);
+                    if ($anchor !== 'vip') {
+                        $insert_at = (int) $idx + 1;
+                    }
+                    break;
+                }
+            }
+            array_splice($order, $insert_at, 0, ['orders']);
+        }
         if (($credits_on || $balance_on) && !in_array('credits', $order, true)) {
             $order[] = 'credits';
         }
@@ -134,6 +158,9 @@ class Center {
             if ($key === 'vip' && !$vip_on) {
                 continue;
             }
+            if ($key === 'orders' && !$orders_on) {
+                continue;
+            }
             $panel = $definitions[$key];
             if ($key === 'credits' && $balance_on) {
                 $panel['label'] = __('我的资产', 'aksrt');