feat(admin): Add group filtering for account listings

- Add groupID parameter to ListAccounts and ListWithFilters methods
- Implement account filtering by group ID in repository query
- Add group query parameter parsing in account handler
- Update all ListAccounts/ListWithFilters call sites with groupID parameter
- Add group filter UI component to AccountTableFilters
- Add i18n translations for group filter label in English and Chinese
- Update API contract and test stubs to reflect new signature
- Enable filtering accounts by their assigned groups in admin panel

frontend/src/components/account/AccountGroupsCell.vue

@@ -41,7 +41,7 @@
         >
           <div class="mb-2 flex items-center justify-between">
             <span class="text-xs font-medium text-gray-500 dark:text-gray-400">
-              {{ t('admin.accounts.allGroups', { count: groups.length }) }}
+              {{ t('admin.accounts.groupCountTotal', { count: groups.length }) }}
             </span>
             <button
               @click="showPopover = false"

frontend/src/components/admin/account/AccountTableFilters.vue

@@ -10,16 +10,21 @@
     <Select :model-value="filters.platform" class="w-40" :options="pOpts" @update:model-value="updatePlatform" @change="$emit('change')" />
     <Select :model-value="filters.type" class="w-40" :options="tOpts" @update:model-value="updateType" @change="$emit('change')" />
     <Select :model-value="filters.status" class="w-40" :options="sOpts" @update:model-value="updateStatus" @change="$emit('change')" />
+    <Select :model-value="filters.group" class="w-40" :options="gOpts" @update:model-value="updateGroup" @change="$emit('change')" />
   </div>
 </template>
 
 <script setup lang="ts">
 import { computed } from 'vue'; import { useI18n } from 'vue-i18n'; import Select from '@/components/common/Select.vue'; import SearchInput from '@/components/common/SearchInput.vue'
-const props = defineProps(['searchQuery', 'filters']); const emit = defineEmits(['update:searchQuery', 'update:filters', 'change']); const { t } = useI18n()
+import type { AdminGroup } from '@/types'
+const props = defineProps<{ searchQuery: string; filters: Record<string, any>; groups?: AdminGroup[] }>()
+const emit = defineEmits(['update:searchQuery', 'update:filters', 'change']); const { t } = useI18n()
 const updatePlatform = (value: string | number | boolean | null) => { emit('update:filters', { ...props.filters, platform: value }) }
 const updateType = (value: string | number | boolean | null) => { emit('update:filters', { ...props.filters, type: value }) }
 const updateStatus = (value: string | number | boolean | null) => { emit('update:filters', { ...props.filters, status: value }) }
+const updateGroup = (value: string | number | boolean | null) => { emit('update:filters', { ...props.filters, group: value }) }
 const pOpts = computed(() => [{ value: '', label: t('admin.accounts.allPlatforms') }, { value: 'anthropic', label: 'Anthropic' }, { value: 'openai', label: 'OpenAI' }, { value: 'gemini', label: 'Gemini' }, { value: 'antigravity', label: 'Antigravity' }])
 const tOpts = computed(() => [{ value: '', label: t('admin.accounts.allTypes') }, { value: 'oauth', label: t('admin.accounts.oauthType') }, { value: 'setup-token', label: t('admin.accounts.setupToken') }, { value: 'apikey', label: t('admin.accounts.apiKey') }])
 const sOpts = computed(() => [{ value: '', label: t('admin.accounts.allStatus') }, { value: 'active', label: t('admin.accounts.status.active') }, { value: 'inactive', label: t('admin.accounts.status.inactive') }, { value: 'error', label: t('admin.accounts.status.error') }, { value: 'rate_limited', label: t('admin.accounts.status.rateLimited') }])
+const gOpts = computed(() => [{ value: '', label: t('admin.accounts.allGroups') }, ...(props.groups || []).map(g => ({ value: String(g.id), label: g.name }))])
 </script>