GET /v2/social-media/{id}

Returns approved bytes after fresh authentication and current Community parent/ancestor authorization or Messaging membership/block authorization. An unbound ready upload is previewable only by its uploader; a public group does not grant nonmember access. Authorization and media state are checked again after storage retrieval before bytes are sent. Pending, expired, deleted or currently inaccessible media returns 404. Subsequent reads fail after revocation; bytes already delivered cannot be recalled. Every response is private, no-store and nosniff. Disabling new writes does not remove this reader.