StoreCurrentAsPreset only used ContentItem.ContainerArt for the stored
artwork URL. For Spotify (and some other streaming sources) the speaker
populates the top-level NowPlaying.Art.URL field instead, leaving
ContainerArt empty, which caused preset tiles to show as text-only.
When ContainerArt is empty and Art.URL is present with artImageStatus
IMAGE_PRESENT, copy the URL into a shallow-copy of the ContentItem
before storing it. Devices where ContainerArt is already set are
unaffected.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>