- Use the standard "Authorization: MediaBrowser ..., Token=..." header
instead of the legacy X-Emby-Authorization / X-Emby-Token headers,
which are no longer accepted by Jellyfin 10.12.
- _make_request now returns True on empty successful responses (204)
and None only on errors, so failed tag updates are reported as failures.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>