feature: a minimal implementation of staff management is done.

frontend/src/lib/api/staff.ts

@@ -0,0 +1,63 @@
+import { apiClient } from './client';
+
+export interface StaffMemberDto {
+  id: string;
+  userId: string;
+  email: string;
+  name: string;
+  isOwner: boolean;
+  permissions: string[] | null;
+}
+
+export interface StaffListResponse {
+  success: boolean;
+  data: {
+    members: StaffMemberDto[];
+    seats: {
+      used: number;
+      limit: number | null;
+      unlimited: boolean;
+    };
+  };
+}
+
+export interface InviteStaffResponse {
+  success: boolean;
+  data: {
+    membershipId: string;
+    userId: string;
+    email: string;
+    temporaryPassword: string | null;
+  };
+}
+
+export const staffApi = {
+  list: async (): Promise<StaffListResponse> => {
+    const response = await apiClient.get('/staff');
+    return response.data;
+  },
+
+  invite: async (body: {
+    email: string;
+    name: string;
+    permissionNames: string[];
+  }): Promise<InviteStaffResponse> => {
+    const response = await apiClient.post('/staff/invite', body);
+    return response.data;
+  },
+
+  updateMember: async (
+    membershipId: string,
+    body: { name?: string; permissionNames?: string[] },
+  ): Promise<{ success: boolean; message: string }> => {
+    const response = await apiClient.patch(`/staff/members/${membershipId}`, body);
+    return response.data;
+  },
+
+  removeMember: async (
+    membershipId: string,
+  ): Promise<{ success: boolean; message: string }> => {
+    const response = await apiClient.delete(`/staff/members/${membershipId}`);
+    return response.data;
+  },
+};