feat: 实现前端卡密管理界面

- 卡密列表展示与分页功能

- 单个/批量创建卡密

- 卡密删除与批量删除

- 卡密导出功能 (file-saver)

- 启用/禁用状态切换

- 状态判断 (有效/已使用/已失效)

- Toast 通知系统 (vue-sonner)

- 登录页面错误提示优化

- 后端登录错误消息中文化

frontend/src/api/accounts.ts

@@ -0,0 +1,58 @@
+import request from './request'
+
+export interface Account {
+    id: number
+    team_account_id: string
+    name: string
+    is_active: boolean
+    seats_in_use: number
+    seats_entitled: number
+    created_at: string
+    updated_at: string
+}
+
+export interface AccountsResponse {
+    success: boolean
+    data?: Account[]
+    total?: number
+    page?: number
+    page_size?: number
+    message?: string
+}
+
+export interface AccountResponse {
+    success: boolean
+    data?: Account
+    message?: string
+}
+
+export interface CreateAccountRequest {
+    team_account_id: string
+    auth_token: string
+    name?: string
+}
+
+export interface PaginationParams {
+    page?: number
+    page_size?: number
+}
+
+export function getAccounts(params?: PaginationParams) {
+    const searchParams = new URLSearchParams()
+    if (params?.page) searchParams.set('page', String(params.page))
+    if (params?.page_size) searchParams.set('page_size', String(params.page_size))
+    const query = searchParams.toString()
+    return request.get<AccountsResponse>(`/api/accounts${query ? `?${query}` : ''}`)
+}
+
+export function createAccount(data: CreateAccountRequest) {
+    return request.post<AccountResponse>('/api/accounts/create', data)
+}
+
+export function refreshAccount(id: number) {
+    return request.post<AccountResponse>(`/api/accounts/refresh?id=${id}`)
+}
+
+export function deleteAccount(id: number) {
+    return request.delete(`/api/accounts/delete?id=${id}`)
+}