fix(slint): spinner on home/album/artist + dedupe only in All-tab carousel

Home, Album and Artist views now show the rotating LoadingSpinner (same
as search) above a label while the initial load runs, replacing the
bare Loading… text.

The top-result-artist dedupe moved from map_search_all into apply_search
and replace_category: the full artists list is kept in SearchState.artists
(used by the Artists tab grid), and a separate artists-carousel drops the
duplicate next to the Most-popular hero on the All tab.

cc

crates/qbz-slint/ui/search/SearchResultsView.slint

@@ -489,11 +489,13 @@ export component SearchResultsView inherits Rectangle {
                         }
                     }
 
-                    // Artists carousel — fills the rest of the row.
-                    if SearchState.artists.length > 0: ArtistCarousel {
+                    // Artists carousel — fills the rest of the row. Uses
+                    // the carousel-only list so the Most-popular hero is
+                    // not duplicated next to it.
+                    if SearchState.artists-carousel.length > 0: ArtistCarousel {
                         horizontal-stretch: 1;
                         title: @tr("Artists");
-                        artists: SearchState.artists;
+                        artists: SearchState.artists-carousel;
                         show-view-all: true;
                         artist-clicked(id) => { root.open-artist(id); }
                         media-action(k, i, a) => { root.media-action(k, i, a); }