feat: 实现注册优惠码功能

- 支持创建/编辑/删除优惠码，设置赠送金额和使用限制
  - 注册页面实时验证优惠码并显示赠送金额
  - 支持 URL 参数自动填充 (?promo=CODE)
  - 添加优惠码验证接口速率限制
  - 使用数据库行锁防止并发超限
  - 新增后台优惠码管理页面，支持复制注册链接

frontend/src/api/admin/index.ts

@@ -9,6 +9,7 @@ import groupsAPI from './groups'
 import accountsAPI from './accounts'
 import proxiesAPI from './proxies'
 import redeemAPI from './redeem'
+import promoAPI from './promo'
 import settingsAPI from './settings'
 import systemAPI from './system'
 import subscriptionsAPI from './subscriptions'
@@ -27,6 +28,7 @@ export const adminAPI = {
   accounts: accountsAPI,
   proxies: proxiesAPI,
   redeem: redeemAPI,
+  promo: promoAPI,
   settings: settingsAPI,
   system: systemAPI,
   subscriptions: subscriptionsAPI,
@@ -43,6 +45,7 @@ export {
   accountsAPI,
   proxiesAPI,
   redeemAPI,
+  promoAPI,
   settingsAPI,
   systemAPI,
   subscriptionsAPI,

frontend/src/api/admin/promo.ts

@@ -0,0 +1,69 @@
+/**
+ * Admin Promo Codes API endpoints
+ */
+
+import { apiClient } from '../client'
+import type {
+  PromoCode,
+  PromoCodeUsage,
+  CreatePromoCodeRequest,
+  UpdatePromoCodeRequest,
+  BasePaginationResponse
+} from '@/types'
+
+export async function list(
+  page: number = 1,
+  pageSize: number = 20,
+  filters?: {
+    status?: string
+    search?: string
+  }
+): Promise<BasePaginationResponse<PromoCode>> {
+  const { data } = await apiClient.get<BasePaginationResponse<PromoCode>>('/admin/promo-codes', {
+    params: { page, page_size: pageSize, ...filters }
+  })
+  return data
+}
+
+export async function getById(id: number): Promise<PromoCode> {
+  const { data } = await apiClient.get<PromoCode>(`/admin/promo-codes/${id}`)
+  return data
+}
+
+export async function create(request: CreatePromoCodeRequest): Promise<PromoCode> {
+  const { data } = await apiClient.post<PromoCode>('/admin/promo-codes', request)
+  return data
+}
+
+export async function update(id: number, request: UpdatePromoCodeRequest): Promise<PromoCode> {
+  const { data } = await apiClient.put<PromoCode>(`/admin/promo-codes/${id}`, request)
+  return data
+}
+
+export async function deleteCode(id: number): Promise<{ message: string }> {
+  const { data } = await apiClient.delete<{ message: string }>(`/admin/promo-codes/${id}`)
+  return data
+}
+
+export async function getUsages(
+  id: number,
+  page: number = 1,
+  pageSize: number = 20
+): Promise<BasePaginationResponse<PromoCodeUsage>> {
+  const { data } = await apiClient.get<BasePaginationResponse<PromoCodeUsage>>(
+    `/admin/promo-codes/${id}/usages`,
+    { params: { page, page_size: pageSize } }
+  )
+  return data
+}
+
+const promoAPI = {
+  list,
+  getById,
+  create,
+  update,
+  delete: deleteCode,
+  getUsages
+}
+
+export default promoAPI

frontend/src/api/auth.ts

@@ -113,6 +113,26 @@ export async function sendVerifyCode(
   return data
 }
 
+/**
+ * Validate promo code response
+ */
+export interface ValidatePromoCodeResponse {
+  valid: boolean
+  bonus_amount?: number
+  error_code?: string
+  message?: string
+}
+
+/**
+ * Validate promo code (public endpoint, no auth required)
+ * @param code - Promo code to validate
+ * @returns Validation result with bonus amount if valid
+ */
+export async function validatePromoCode(code: string): Promise<ValidatePromoCodeResponse> {
+  const { data } = await apiClient.post<ValidatePromoCodeResponse>('/auth/validate-promo-code', { code })
+  return data
+}
+
 export const authAPI = {
   login,
   register,
@@ -123,7 +143,8 @@ export const authAPI = {
   getAuthToken,
   clearAuthToken,
   getPublicSettings,
-  sendVerifyCode
+  sendVerifyCode,
+  validatePromoCode
 }
 
 export default authAPI