Plex / Jellyfin / Navidrome each defined a near-identical
XTrackInfo (id / title / artist / album / duration / track_number /
year / rating) and XPlaylistInfo (id / title / description /
duration / leaf_count / tracks). Three classes that grew up by
copy-paste — not a real contract difference.
Lifted both to core/media_server/types.py as canonical TrackInfo +
PlaylistInfo. Per-server constructors live as classmethods on the
unified class (TrackInfo.from_plex_track, PlaylistInfo.from_plex_playlist)
matching the metadata Album.from_X_dict pattern Cin's POC uses.
Heavy plexapi imports stay lazy under TYPE_CHECKING.
- core/plex_client.py / jellyfin_client.py / navidrome_client.py:
per-server XTrackInfo / XPlaylistInfo dataclass definitions
removed; each module now imports TrackInfo + PlaylistInfo from
the neutral package and uses the shared name internally.
- core/matching_engine.py: was annotating callers with PlexTrackInfo
even though sync_service hands it Jellyfin / Navidrome instances
at runtime when those servers are active. Annotation is now the
unified TrackInfo, so signatures match the actual contract.
- services/sync_service.py: same import + annotation update.