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.

assets/css/routes/user-center/credits.css

@@ -6,6 +6,24 @@
   box-shadow: none;
 }
 
+/* Dual assets: wallet + points cards stack with gap */
+.uc-wallet-grid {
+  margin-bottom: 16px;
+}
+
+.uc-balance-card--wallet .uc-balance-card__bg--wallet,
+.uc-balance-card__bg--wallet {
+  background: linear-gradient(135deg, #0f766e 0%, #14b8a6 45%, #2dd4bf 100%);
+}
+
+.uc-balance-card + .uc-balance-card {
+  margin-top: 12px;
+}
+
+.uc-transactions--wallet {
+  margin-bottom: 20px;
+}
+
 .uc-content #panel-credits .uc-transactions {
   background: transparent;
   border: 0;