Lists the file categories and files visible to the caller for the specified employee. This is a metadata listing (names, sizes, permissions); to download a file's content use get-employee-file. The response format is controlled by the Accept header: send application/json for JSON or omit/send anything else for XML. Only categories and files the caller is permitted to see are included; employees viewing their own profile also see files shared with them. Returns 404 when the employee has no accessible categories.