* feat(subtitles): generate Japanese subtitles during Jellyfin playback
- Read the item's original file via toJellyfinOriginalStreamUrl and write output to a temp dir
- Transcoded playback uses Jellyfin's audio index and only external references
- Show Jellyfin media by title and redact URL tokens in subprocess errors
- Update overlay copy, docs, and changelog fragment
* fix(subtitles): redact full stream tokens and reuse one Jellyfin output folder
* test(subtitles): make Jellyfin output path assertions platform-neutral
- Compare dirname/basename via node:path instead of POSIX-only regexes
- Assert the full sub-add command uses the generated output path
