refactor(keys): 优化分组选项显示与代码复用

- 删除冗余的 vite.config.js，统一使用 TypeScript 配置
- 创建 GroupOptionItem 组件封装分组选项 UI 逻辑（GroupBadge + 描述 + 勾选状态）
- 在密钥页面的分组选择器中显示分组描述文字
- 添加选中状态的勾选图标，提升交互体验
- 优化描述文字左对齐和截断显示效果
- 消除代码重复，简化维护成本

frontend/src/components/common/GroupOptionItem.vue

@@ -0,0 +1,52 @@
+<template>
+  <div class="flex min-w-0 flex-1 items-center justify-between gap-2">
+    <div
+      class="flex min-w-0 flex-1 flex-col items-start gap-1"
+      :title="description || undefined"
+    >
+      <GroupBadge
+        :name="name"
+        :platform="platform"
+        :subscription-type="subscriptionType"
+        :rate-multiplier="rateMultiplier"
+      />
+      <span
+        v-if="description"
+        class="w-full truncate text-left text-xs text-gray-500 dark:text-gray-400"
+      >
+        {{ description }}
+      </span>
+    </div>
+    <svg
+      v-if="showCheckmark && selected"
+      class="h-4 w-4 shrink-0 text-primary-600 dark:text-primary-400"
+      fill="none"
+      stroke="currentColor"
+      viewBox="0 0 24 24"
+      stroke-width="2"
+    >
+      <path stroke-linecap="round" stroke-linejoin="round" d="M5 13l4 4L19 7" />
+    </svg>
+  </div>
+</template>
+
+<script setup lang="ts">
+import GroupBadge from './GroupBadge.vue'
+import type { SubscriptionType, GroupPlatform } from '@/types'
+
+interface Props {
+  name: string
+  platform: GroupPlatform
+  subscriptionType?: SubscriptionType
+  rateMultiplier?: number
+  description?: string | null
+  selected?: boolean
+  showCheckmark?: boolean
+}
+
+withDefaults(defineProps<Props>(), {
+  subscriptionType: 'standard',
+  selected: false,
+  showCheckmark: true
+})
+</script>