feat(client): 部门管理与员工创建增强(F32)

- 新增部门管理页：列表/创建/归档
- 用户创建支持选择部门与直属上级
- 补齐 departments/employees API 封装与导航入口

client/src/api/employees.ts

@@ -0,0 +1,41 @@
+import { apiRequestData } from "./http";
+
+export type EmployeeStatus = "active" | "archived";
+
+export type EmployeeSummary = {
+  id: string;
+  employeeNo: string;
+  name: string;
+  phone: string;
+  email: string;
+  status: EmployeeStatus;
+  departmentId: string;
+  directManagerId: string | null;
+  title: string;
+  roleCodes: string[];
+  createdAt: string | null;
+  updatedAt: string | null;
+};
+
+export type EmployeeListResponse = {
+  page: number;
+  pageSize: number;
+  total: number;
+  items: EmployeeSummary[];
+};
+
+export async function fetchEmployees(params: {
+  page: number;
+  pageSize: number;
+  status?: EmployeeStatus;
+  q?: string;
+}) {
+  const search = new URLSearchParams();
+  search.set("page", String(params.page));
+  search.set("pageSize", String(params.pageSize));
+  if (params.status) search.set("status", params.status);
+  if (params.q) search.set("q", params.q);
+
+  return apiRequestData<EmployeeListResponse>(`/api/employees?${search.toString()}`);
+}
+