Two bugs with one root: the card bound the playlist's `images*` lists, which
are MEMBER-ALBUM covers, not the playlist's own artwork. So a Qobuz editorial
playlist showed one of its albums' sleeves, and a user playlist — which has no
`images*` at all — showed nothing.
Qobuz playlists carry their graphic in `image_rectangle`, which the model did
not deserialize; the field is added (additive, `serde(default)`, and Playlist
is only ever built through serde) and the card prefers it, contain-fitted so
the artwork is not cropped. Playlists without one fall back to the member-cover
mosaic, reusing the collage the sidebar already draws rather than a second
implementation. Both the All-tab grid and its list mode are covered — the 44px
list thumb binds the same map and would otherwise have gone blank.
cc