Jellyfin apt repo requires correct Debian codename

Jellyfin repo has separate packages per Debian release. Bookworm packages depend on libs not in trixie. Use `trixie` as codename — confirm with version suffix `+deb13`.

Use trixie codename for Jellyfin on Debian 13. Discovered during Jellyfin deployment (2026-03-11).
Affected entities:Jellyfin