feat(invitation): 支持分销站点自主配置返利比例与权限隔离

- 后端新增分站专属配置及审计接口（/api/distribution/invitation-config 等），基于分站管理员严格鉴权隔离
- 分销独立后台新增「邀请返利设置」页面（Invitations.tsx），支持分站管理员自主开启/调整返利比例并查看本站流水
- 主站后台邀请接口路径补齐 /admin 前缀，解决 404/401 鉴权作用域问题
- 验证方式：backend 单元测试全数通过，distribution-admin 类型与构建检查通过

distribution-admin/src/api.ts

@@ -880,3 +880,85 @@ export async function testSiteSMSConfig(siteID: number, payload: TestSiteSMSConf
   const resp = await api.post<ApiResponse<{ message: string }>>(`/admin/distribution/sites/${siteID}/sms-config/test`, payload)
   return extract(resp)
 }
+
+export interface InvitationRebateConfig {
+  distribution_site_id: number
+  first_month_rate: number
+  second_month_rate: number
+  subsequent_rate: number
+  enabled: boolean
+  updated_at?: string
+}
+
+export interface InvitedUserItem {
+  id: number
+  inviter_id: number
+  inviter_phone?: string
+  inviter_nickname?: string
+  invitee_id: number
+  invitee_phone?: string
+  invitee_nickname?: string
+  invite_code: string
+  status: string
+  verified_at?: string
+  created_at: string
+}
+
+export interface RebateLedgerItem {
+  id: number
+  order_id: number
+  order_no: string
+  inviter_id: number
+  inviter_phone?: string
+  inviter_nickname?: string
+  invitee_id: number
+  invitee_phone?: string
+  invitee_nickname?: string
+  trade_role: 'buyer' | 'seller'
+  order_profit_basis_cent: number
+  single_side_basis_cent: number
+  rate_applied: number
+  days_since_verified: number
+  cycle_stage: string
+  rebate_amount_cent: number
+  status: string
+  settled_at: string
+}
+
+export async function fetchSiteInvitationConfig(siteID?: number): Promise<InvitationRebateConfig> {
+  const url = siteID ? `/distribution/sites/${siteID}/invitation-config` : '/distribution/invitation-config'
+  const resp = await api.get<ApiResponse<InvitationRebateConfig>>(url)
+  return extract(resp)
+}
+
+export async function updateSiteInvitationConfig(
+  siteID: number,
+  payload: {
+    first_month_rate: number
+    second_month_rate: number
+    subsequent_rate: number
+    enabled: boolean
+  }
+): Promise<InvitationRebateConfig> {
+  const url = siteID ? `/distribution/sites/${siteID}/invitation-config` : '/distribution/invitation-config'
+  const resp = await api.put<ApiResponse<InvitationRebateConfig>>(url, payload)
+  return extract(resp)
+}
+
+export async function fetchSiteInvitations(
+  siteID: number,
+  params: { page: number; page_size: number; phone?: string; invite_code?: string }
+): Promise<{ items: InvitedUserItem[]; total: number; page: number; page_size: number }> {
+  const url = siteID ? `/distribution/sites/${siteID}/invitations` : '/distribution/invitations'
+  const resp = await api.get<ApiResponse<{ items: InvitedUserItem[]; total: number; page: number; page_size: number }>>(url, { params })
+  return extract(resp)
+}
+
+export async function fetchSiteRebates(
+  siteID: number,
+  params: { page: number; page_size: number; order_no?: string; inviter_phone?: string; invitee_phone?: string }
+): Promise<{ items: RebateLedgerItem[]; total: number; page: number; page_size: number }> {
+  const url = siteID ? `/distribution/sites/${siteID}/invitation-rebates` : '/distribution/invitation-rebates'
+  const resp = await api.get<ApiResponse<{ items: RebateLedgerItem[]; total: number; page: number; page_size: number }>>(url, { params })
+  return extract(resp)
+}