fix(polish): 订单购物车论坛粉边软化 + 论坛付费帖购链路

- 购物车/商品/论坛表面复用 #77 soft recipe（mix 边 + soft ring）
- 论坛 visibility=pay：订单 resource + 余额扣费闭环
- VIP 价/免费解锁 + 购买 CTA/AJAX，复用现有 Order/Credits

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

assets/css/routes/commerce.css

@@ -43,13 +43,13 @@
 
 .aksrt-commerce-header__nav-item:hover {
   color: var(--color-primary, #f04494);
-  border-color: color-mix(in srgb, var(--color-primary, #f04494) 35%, transparent);
+  border-color: color-mix(in srgb, var(--color-primary, #f04494) 45%, transparent);
 }
 
 .aksrt-commerce-header__nav-item.is-active {
   color: var(--color-on-primary, #fff);
   background: var(--color-primary, #f04494);
-  border-color: var(--color-primary, #f04494);
+  border-color: transparent;
 }
 
 /* Soften revenue dashboard cards — task-first, not ops console */