feat(user-center): add cash wallet balance separate from credits

Introduce AKSRT_Balance (user_meta aksrt_balance + balance_log) for
Zibll-like pay_balance wallet. User center assets panel shows wallet
and points; balance gateway/card-pass/refunds credit cash when enabled.

inc/classes/class-aksrt-user-center.php

@@ -92,8 +92,16 @@ class AKSRT_User_Center {
         $this->panels = [];
 
         foreach ((array) ($settings['tabs'] ?? []) as $key) {
-            if ($key === 'credits' && (!class_exists('AKSRT_Settings') || !AKSRT_Settings::credits_enabled())) {
-                continue;
+            if ($key === 'credits') {
+                $credits_on = class_exists('AKSRT_Settings') && AKSRT_Settings::credits_enabled();
+                $balance_on = class_exists('AKSRT_Balance') && AKSRT_Balance::enabled();
+                if (!$credits_on && !$balance_on) {
+                    continue;
+                }
+                if ($balance_on) {
+                    $definitions['credits']['label'] = __('我的资产', 'aksrt');
+                    $definitions['credits']['icon']  = 'wallet';
+                }
             }
 
             if (isset($definitions[$key])) {
@@ -101,6 +109,18 @@ class AKSRT_User_Center {
             }
         }
 
+        // Ensure assets panel when wallet and/or credits enabled (even if tabs list omitted credits).
+        $credits_on = class_exists('AKSRT_Settings') && AKSRT_Settings::credits_enabled();
+        $balance_on = class_exists('AKSRT_Balance') && AKSRT_Balance::enabled();
+        if (!isset($this->panels['credits']) && ($credits_on || $balance_on)) {
+            $panel = $definitions['credits'];
+            if ($balance_on) {
+                $panel['label'] = __('我的资产', 'aksrt');
+                $panel['icon']  = 'wallet';
+            }
+            $this->panels['credits'] = $panel;
+        }
+
         if (!isset($this->panels['settings'])) {
             $this->panels['settings'] = $definitions['settings'];
         }