refactor(frontend): 优化 Gemini 配额显示，参考 Antigravity 样式

- 简化标签：将 "RPD Pro/Flash" 改为 "Pro/Flash"，避免文字截断
- 添加账号类型徽章（Free/Pro/Ultra），带颜色区分
- 添加帮助图标（?），悬停显示限流政策和官方文档链接
- 重构显示布局：账号类型 + 两行配额（Pro/Flash）
- 移除冗余的 AccountQuotaInfo 组件调用

frontend/src/components/account/AccountQuotaInfo.vue

@@ -10,7 +10,7 @@
       v-if="!isRateLimited"
       class="text-xs text-gray-400 dark:text-gray-500"
     >
-      未限流
+      {{ t('admin.accounts.gemini.rateLimit.ok') }}
     </span>
     <span
       v-else
@@ -21,19 +21,22 @@
           : 'text-amber-600 dark:text-amber-400'
       ]"
     >
-      限流 {{ resetCountdown }}
+      {{ t('admin.accounts.gemini.rateLimit.limited', { time: resetCountdown }) }}
     </span>
   </div>
 </template>
 
 <script setup lang="ts">
 import { computed, ref, watch, onUnmounted } from 'vue'
+import { useI18n } from 'vue-i18n'
 import type { Account, GeminiCredentials } from '@/types'
 
 const props = defineProps<{
   account: Account
 }>()
 
+const { t } = useI18n()
+
 const now = ref(new Date())
 let timer: ReturnType<typeof setInterval> | null = null
 
@@ -98,7 +101,7 @@ const resetCountdown = computed(() => {
   if (Number.isNaN(resetTime)) return '-'
 
   const diffMs = resetTime - now.value.getTime()
-  if (diffMs <= 0) return 'now'
+  if (diffMs <= 0) return t('admin.accounts.gemini.rateLimit.now')
 
   const diffSeconds = Math.floor(diffMs / 1000)
   const diffMinutes = Math.floor(diffSeconds / 60)