MIME 验证：存储与安全设计
将声明的 MIME 类型和扩展名仅作为提示，通过嗅探或检查验证内容，并在未知或不匹配的上传文件进入服务路径之前将其隔离。
Governs object deletion against retention profiles, legal hold flags, ownership evidence, and immutable audit records without providing legal advice or deleting data under active hold.