fix(frontend): 修复重构页面的遗漏问题

- 添加 en.ts 中缺失的 admin.redeem.types 翻译
- RedeemView 状态筛选器添加 expired 选项
- SubscriptionsView 用量进度条添加 null/undefined 兜底
- SubscriptionsView 添加 validity_days 表单校验
- GroupsView/ProxiesView 搜索图标添加 dark mode 样式

frontend/src/views/admin/ProxiesView.vue

@@ -9,7 +9,7 @@
             <!-- Search -->
             <div class="relative w-full sm:flex-1 sm:min-w-[14rem] sm:max-w-md">
               <svg
-                class="absolute left-3 top-1/2 h-5 w-5 -translate-y-1/2 text-gray-400"
+                class="absolute left-3 top-1/2 h-5 w-5 -translate-y-1/2 text-gray-400 dark:text-gray-500"
                 fill="none"
                 stroke="currentColor"
                 viewBox="0 0 24 24"