实现租户坐席账号管理

新增 /api/staff 列表/创建/更新/禁用，按租户坐席配额校验；系统设置增加坐席账号页支持增改禁与配额展示。

web/src/services/api.ts

@@ -223,6 +223,28 @@ export const getChannels = () => get<Channel[]>('/channels')
 export const createChannel = (data: { type: string; name?: string }) => post<Channel>('/channels', data)
 export const updateChannel = (id: number, data: { name?: string; status?: string }) => put<Channel>(`/channels/${id}`, data)
 
+// 坐席账号
+export interface StaffUser {
+  id: number
+  username: string
+  nickname: string
+  role: string
+  status: string
+  created_at: string
+  last_online_at?: string
+}
+export interface StaffListResult {
+  list: StaffUser[]
+  seat_limit: number
+  seat_used: number
+}
+export const getStaff = () => get<StaffListResult>('/staff')
+export const createStaff = (data: { username: string; password: string; nickname?: string; role?: string }) =>
+  post<StaffUser>('/staff', data)
+export const updateStaff = (id: number, data: { nickname?: string; role?: string; status?: string; password?: string }) =>
+  put<StaffUser>(`/staff/${id}`, data)
+export const deleteStaff = (id: number) => del(`/staff/${id}`)
+
 // Tenant settings
 export type WorkHours = Record<string, string>
 export interface TenantSettings {