fix(slint): search results 1:1 with Tauri

- Most popular: a crowned hero inline with the artists carousel; its
  cover now resolves (a dedicated artwork target was missing).
- Artists: a real carousel on the All tab, ArtistCard restyled to the
  Tauri For-You tile with a Follow chip (favorites the artist) shown
  when the user does not follow it.
- Playlists: a PlaylistCarousel of PlaylistCard, with a count-based
  PlaylistCollage (1/2/3/4-up) instead of a flat row list.
- Carousels gained a View all link; result counts removed from titles.
- searchType filter is a styled radio row (ring + accent dot) at the
  top right with a clear button, not a dropdown.
- Title fixed to Search Results.
- QbzCore::favorite_artist_ids backs the follow state.

cc

crates/qbz-slint/ui/assets/icons/crown.svg

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crates/qbz-slint/ui/assets/icons/user-plus.svg

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+<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="#ffffff" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M2 21a8 8 0 0 1 13.292-6"/><circle cx="10" cy="8" r="5"/><path d="M19 16v6"/><path d="M22 19h-6"/></svg>