feat: 订阅管理增强、商品名称配置、余额充值开关

- R1: 用户订阅搜索改为模糊关键词（邮箱/用户名/备注/APIKey）
- R2: "分组状态"列名改为"Sub2API 状态"
- R3: 订阅套餐可配置支付商品名称（productName）
- R4: 订阅订单校验 subscription_type 必须为 subscription
- R5: 渠道管理配置余额充值商品名前缀/后缀
- R6: 渠道管理可关闭余额充值，前端隐藏入口，API 拒绝
- R7: 所有入口关闭时显示"入口被管理员关闭"提示
- fix: easy-pay client 测试 mock 方式修复（vi.fn + 参数快照）

src/components/MainTabs.tsx

@@ -8,17 +8,22 @@ interface MainTabsProps {
   activeTab: 'topup' | 'subscribe';
   onTabChange: (tab: 'topup' | 'subscribe') => void;
   showSubscribeTab: boolean;
+  showTopUpTab?: boolean;
   isDark: boolean;
   locale: Locale;
 }
 
-export default function MainTabs({ activeTab, onTabChange, showSubscribeTab, isDark, locale }: MainTabsProps) {
+export default function MainTabs({ activeTab, onTabChange, showSubscribeTab, showTopUpTab = true, isDark, locale }: MainTabsProps) {
   if (!showSubscribeTab) return null;
 
-  const tabs: { key: 'topup' | 'subscribe'; label: string }[] = [
-    { key: 'topup', label: pickLocaleText(locale, '按量付费', 'Pay-as-you-go') },
-    { key: 'subscribe', label: pickLocaleText(locale, '包月套餐', 'Subscription') },
-  ];
+  const tabs: { key: 'topup' | 'subscribe'; label: string }[] = [];
+  if (showTopUpTab) {
+    tabs.push({ key: 'topup', label: pickLocaleText(locale, '按量付费', 'Pay-as-you-go') });
+  }
+  tabs.push({ key: 'subscribe', label: pickLocaleText(locale, '包月套餐', 'Subscription') });
+
+  // 只有一个 tab 时不显示切换器
+  if (tabs.length <= 1) return null;
 
   return (
     <div