[Feature Request] User-Level Permission to Disable Document Downloads

Description Please add a user-level permission or toggle that allows administrators to explicitly enable or disable document downloads for specific users. While there are external methods to restrict downloads, the Paperless-ngx user interface should accurately reflect and enforce these restrictions. This is particularly relevant for environments such as public terminals, kiosks, reception desks, or other shared workstations where users should be able to view documents but not download them. Providing a dedicated permission would improve the user experience here. Users who are unfamiliar with the system often rely on visible UI cues to understand what actions are available to them. Hiding or disabling download functionality when it is not permitted helps reduce confusion, prevents accidental policy violations, and creates a clearer, more intuitive workflow. Administrators can configure a per-user (or per-group) setting that: • Allow or Prevents document downloads &…