get_playlist fails on the new "item" wrapper (Feb 2026 API change)

[maxmaxme]

Since Spotify's Feb 2026 Web API migration, playlist responses wrap each entry in item instead of track (tracks.track → items.item), and track is now marked deprecated.

PlaylistTrack still requires track, so get_playlist and get_playlist_items fail on the new payload:

MissingField: Field "track" of type Item is missing in PlaylistTrack instance
→ InvalidFieldValue: Field "items" of type list[PlaylistTrack] in PlaylistTracks ...
→ InvalidFieldValue: Field "items" of type PlaylistTracks in Playlist ...

Reproduced on spotifyaio==2.0.2: feeding a real playlist-items response (entries with item and no track) to Playlist.from_json / PlaylistTracks raises the above; adding track = item makes it parse.

This is currently breaking the Home Assistant Spotify integration (home-assistant/core#165877).

track is still sent during the deprecation window, so both shapes need to work. I think the cleanest fix is normalizing item → track in PlaylistTrack.__pre_deserialize__, mirroring what Playlist.__pre_deserialize__ already does for tracks → items. Happy to open a PR.

Related: #767 handles a missing items list (metadata-only playlists) but not the track/item rename.