scan-disk backup server: POST /manifest, POST /upload/sign + PUT + POST /upload/done（直传 OSS）, GET /progress?client=
客户端状态: POST /status, GET /status?client=
客户端自动更新: 心跳响应带 update 字段, 客户端直连 OSS 签名地址下载
聊天记录: POST /chat/batch, GET /chat/sessions, GET /chat/messages?client=&session=, GET /chat/search?client=&session=&q=, GET /chat/view
微信账号备注: GET/POST /chat/aliases {profile,alias}
备份文件: GET /files/