feat(auth): 添加 Refresh Token 双 Token 机制

- 添加 /api/refresh-token 接口支持 Token 续期
- 登录接口返回 access_token 和 refresh_token
- 新增 refresh_tokens 表存储 refresh_token
- 部署脚本添加数据库备份和迁移功能
- deploy.sh 添加 4 项 API 测试
- 更新 AGENTS.md 文档

Cargo.toml

@@ -23,6 +23,7 @@ sqlx = { version = "0.8.6", features = ["runtime-tokio-rustls", "postgres", "chr
 uuid = { version = "1", features = ["v4"] }
 tokio = { version = "1", features = ["full"] }
 toml = "0.8"
+base64 = "0.22"
 
 [dev-dependencies]
 tokio = { version = "1", features = ["full"] }