Missing authorization in Warracker Paperless-ngx document linking

Warracker before 1.0.4 contains a missing authorization vulnerability in its Paperless-ngx integration that allows an authenticated, non-administrative user to bypass document ownership restrictions by searching for and linking another user's private document ID to a warranty they own using the `other` document type. Attackers can exploit insufficient authorization checks in the `paperless_search_and_link()` and `serve_paperless_document()` route handlers in file_routes.py to retrieve and disclose private documents belonging to another user via the shared Paperless-ngx API credential, resulting in unauthorized read access and confidentiality loss.