feat: expose user activity timestamps in admin list

frontend/src/i18n/locales/en.ts

@@ -1391,6 +1391,8 @@ export default {
         usage: 'Usage',
         concurrency: 'Concurrency',
         status: 'Status',
+        lastLogin: 'Last Login',
+        lastActive: 'Last Active',
         created: 'Created',
         actions: 'Actions'
       },

frontend/src/i18n/locales/zh.ts

@@ -1417,6 +1417,8 @@ export default {
         usage: '用量',
         concurrency: '并发数',
         status: '状态',
+        lastLogin: '最后登录',
+        lastActive: '最后使用',
         created: '创建时间',
         actions: '操作'
       },

frontend/src/types/index.ts

@@ -47,6 +47,8 @@ export interface User {
   balance_notify_threshold: number | null
   balance_notify_extra_emails: NotifyEmailEntry[]
   subscriptions?: UserSubscription[] // User's active subscriptions
+  last_login_at?: string | null
+  last_active_at?: string | null
   created_at: string
   updated_at: string
 }

frontend/src/views/admin/UsersView.vue

@@ -455,6 +455,18 @@
             <span class="text-sm text-gray-500 dark:text-dark-400">{{ formatDateTime(value) }}</span>
           </template>
 
+          <template #cell-last_login_at="{ value }">
+            <span class="text-sm text-gray-500 dark:text-dark-400">
+              {{ value ? formatDateTime(value) : '-' }}
+            </span>
+          </template>
+
+          <template #cell-last_active_at="{ value }">
+            <span class="text-sm text-gray-500 dark:text-dark-400">
+              {{ value ? formatDateTime(value) : '-' }}
+            </span>
+          </template>
+
           <template #cell-actions="{ row }">
             <div class="flex items-center gap-1">
               <!-- Edit Button -->
@@ -700,6 +712,8 @@ const allColumns = computed<Column[]>(() => [
   { key: 'usage', label: t('admin.users.columns.usage'), sortable: false },
   { key: 'concurrency', label: t('admin.users.columns.concurrency'), sortable: true },
   { key: 'status', label: t('admin.users.columns.status'), sortable: true },
+  { key: 'last_login_at', label: t('admin.users.columns.lastLogin'), sortable: true },
+  { key: 'last_active_at', label: t('admin.users.columns.lastActive'), sortable: true },
   { key: 'created_at', label: t('admin.users.columns.created'), sortable: true },
   { key: 'actions', label: t('admin.users.columns.actions'), sortable: false }
 ])
@@ -714,7 +728,7 @@ const toggleableColumns = computed(() =>
 const hiddenColumns = reactive<Set<string>>(new Set())
 
 // Default hidden columns (columns hidden by default on first load)
-const DEFAULT_HIDDEN_COLUMNS = ['notes', 'groups', 'subscriptions', 'usage', 'concurrency']
+const DEFAULT_HIDDEN_COLUMNS = ['notes', 'groups', 'subscriptions', 'usage', 'concurrency', 'last_login_at', 'last_active_at']
 
 // localStorage key for column settings
 const HIDDEN_COLUMNS_KEY = 'user-hidden-columns'
@@ -787,7 +801,7 @@ const searchQuery = ref('')
 const USER_SORT_STORAGE_KEY = 'admin-users-table-sort'
 const loadInitialSortState = (): { sort_by: string; sort_order: 'asc' | 'desc' } => {
   const fallback = { sort_by: 'created_at', sort_order: 'desc' as 'asc' | 'desc' }
-  const sortable = new Set(['email', 'id', 'username', 'role', 'balance', 'concurrency', 'status', 'created_at'])
+  const sortable = new Set(['email', 'id', 'username', 'role', 'balance', 'concurrency', 'status', 'last_login_at', 'last_active_at', 'created_at'])
   try {
     const raw = localStorage.getItem(USER_SORT_STORAGE_KEY)
     if (!raw) return fallback