feat: 数据库定时备份与恢复（S3 兼容存储，支持 Cloudflare R2）

新增管理员专属的数据库备份与恢复功能：
- 全量 PostgreSQL 备份（pg_dump），gzip 压缩后上传到 S3 兼容存储
- 支持手动备份和 cron 定时备份
- 支持从备份恢复（psql --single-transaction）
- 备份文件自动过期清理（默认 14 天）
- 前端完整管理页面（S3 配置、定时配置、备份列表、恢复/下载/删除）
- 内置 Cloudflare R2 配置教程弹窗
- Dockerfile 从 postgres 镜像多阶段复制 pg_dump/psql，确保版本一致

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/api/admin/backup.ts

@@ -0,0 +1,114 @@
+import { apiClient } from '../client'
+
+export interface BackupS3Config {
+  endpoint: string
+  region: string
+  bucket: string
+  access_key_id: string
+  secret_access_key?: string
+  prefix: string
+  force_path_style: boolean
+}
+
+export interface BackupScheduleConfig {
+  enabled: boolean
+  cron_expr: string
+  retain_days: number
+  retain_count: number
+}
+
+export interface BackupRecord {
+  id: string
+  status: 'pending' | 'running' | 'completed' | 'failed'
+  backup_type: string
+  file_name: string
+  s3_key: string
+  size_bytes: number
+  triggered_by: string
+  error_message?: string
+  started_at: string
+  finished_at?: string
+  expires_at?: string
+}
+
+export interface CreateBackupRequest {
+  expire_days?: number
+}
+
+export interface TestS3Response {
+  ok: boolean
+  message: string
+}
+
+// S3 Config
+export async function getS3Config(): Promise<BackupS3Config> {
+  const { data } = await apiClient.get<BackupS3Config>('/admin/backups/s3-config')
+  return data
+}
+
+export async function updateS3Config(config: BackupS3Config): Promise<BackupS3Config> {
+  const { data } = await apiClient.put<BackupS3Config>('/admin/backups/s3-config', config)
+  return data
+}
+
+export async function testS3Connection(config: BackupS3Config): Promise<TestS3Response> {
+  const { data } = await apiClient.post<TestS3Response>('/admin/backups/s3-config/test', config)
+  return data
+}
+
+// Schedule
+export async function getSchedule(): Promise<BackupScheduleConfig> {
+  const { data } = await apiClient.get<BackupScheduleConfig>('/admin/backups/schedule')
+  return data
+}
+
+export async function updateSchedule(config: BackupScheduleConfig): Promise<BackupScheduleConfig> {
+  const { data } = await apiClient.put<BackupScheduleConfig>('/admin/backups/schedule', config)
+  return data
+}
+
+// Backup operations
+export async function createBackup(req?: CreateBackupRequest): Promise<BackupRecord> {
+  const { data } = await apiClient.post<BackupRecord>('/admin/backups', req || {}, { timeout: 600000 })
+  return data
+}
+
+export async function listBackups(): Promise<{ items: BackupRecord[] }> {
+  const { data } = await apiClient.get<{ items: BackupRecord[] }>('/admin/backups')
+  return data
+}
+
+export async function getBackup(id: string): Promise<BackupRecord> {
+  const { data } = await apiClient.get<BackupRecord>(`/admin/backups/${id}`)
+  return data
+}
+
+export async function deleteBackup(id: string): Promise<void> {
+  await apiClient.delete(`/admin/backups/${id}`)
+}
+
+export async function getDownloadURL(id: string): Promise<{ url: string }> {
+  const { data } = await apiClient.get<{ url: string }>(`/admin/backups/${id}/download-url`)
+  return data
+}
+
+// Restore
+export async function restoreBackup(id: string): Promise<void> {
+  await apiClient.post(`/admin/backups/${id}/restore`, {}, { timeout: 600000 })
+}
+
+export const backupAPI = {
+  getS3Config,
+  updateS3Config,
+  testS3Connection,
+  getSchedule,
+  updateSchedule,
+  createBackup,
+  listBackups,
+  getBackup,
+  deleteBackup,
+  getDownloadURL,
+  restoreBackup,
+}
+
+export default backupAPI

frontend/src/api/admin/index.ts

@@ -23,6 +23,7 @@ import errorPassthroughAPI from './errorPassthrough'
 import dataManagementAPI from './dataManagement'
 import apiKeysAPI from './apiKeys'
 import scheduledTestsAPI from './scheduledTests'
+import backupAPI from './backup'
 
 /**
  * Unified admin API object for convenient access
@@ -47,7 +48,8 @@ export const adminAPI = {
   errorPassthrough: errorPassthroughAPI,
   dataManagement: dataManagementAPI,
   apiKeys: apiKeysAPI,
-  scheduledTests: scheduledTestsAPI
+  scheduledTests: scheduledTestsAPI,
+  backup: backupAPI
 }
 
 export {
@@ -70,7 +72,8 @@ export {
   errorPassthroughAPI,
   dataManagementAPI,
   apiKeysAPI,
-  scheduledTestsAPI
+  scheduledTestsAPI,
+  backupAPI
 }
 
 export default adminAPI