fix(discovery): wire favorite button on browse/see-all pages (#468)

The heart overlay on AlbumCardLite always renders and calls onFavorite, but
VirtualizedFavoritesAlbumGrid never forwarded onFavorite/isFavorite, so the
button was dead on every discover see-all page. Thread both through the grid
and wire DiscoverBrowseView to the shared albumFavoritesStore (same pattern as
the collapsed DiscoveryView). Fixes favoriting across all six browse pages.

cc

src/lib/components/VirtualizedFavoritesAlbumGrid.svelte

@@ -53,6 +53,8 @@
     onLoadMore?: () => void;
     isLoadingMore?: boolean;
     onAddAlbumToPlaylist?: (albumId: string) => void;
+    onAlbumFavorite?: (albumId: string) => void;
+    isAlbumFavorite?: (albumId: string) => boolean;
   }
 
   let {
@@ -79,6 +81,8 @@
     onLoadMore,
     isLoadingMore = false,
     onAddAlbumToPlaylist,
+    onAlbumFavorite,
+    isAlbumFavorite,
   }: Props = $props();
 
   // Constants
@@ -330,6 +334,8 @@
                   onShareSonglink={onAlbumShareSonglink ? () => onAlbumShareSonglink(album.id) : undefined}
                   onDownload={onAlbumDownload ? () => onAlbumDownload(album.id) : undefined}
                   onReDownloadAlbum={onReDownloadAlbum ? () => onReDownloadAlbum(album.id) : undefined}
+                  isFavorite={isAlbumFavorite?.(album.id) ?? false}
+                  onFavorite={onAlbumFavorite ? () => onAlbumFavorite(album.id) : undefined}
                   onClick={() => handleAlbumClickEvent(album.id)}
                 />
               </div>

src/lib/components/views/DiscoverBrowseView.svelte

@@ -9,6 +9,11 @@
     getSelectedGenreIds,
     type GenreFilterContext
   } from '$lib/stores/genreFilterStore';
+  import {
+    isAlbumFavorite,
+    toggleAlbumFavorite,
+    subscribe as subscribeAlbumFavs,
+  } from '$lib/stores/albumFavoritesStore';
 
   interface DiscoverAlbum {
     id: string;
@@ -94,6 +99,20 @@
   };
   const genreContext = $derived(GENRE_CONTEXT_MAP[endpointType]);
 
+  // Album favorite state — reactive against the shared albumFavoritesStore so
+  // the heart on each card reflects (and toggles) real favorite status. The
+  // collapsed Discovery view already wires this; the "see all" browse pages
+  // were missing it, so the heart did nothing here (issue #468).
+  let favoritesVersion = $state(0);
+  $effect(() => {
+    const unsub = subscribeAlbumFavs(() => { favoritesVersion++; });
+    return unsub;
+  });
+  function isFav(albumId: string): boolean {
+    void favoritesVersion;
+    return isAlbumFavorite(albumId);
+  }
+
   // State
   let albums = $state<FavoriteAlbum[]>([]);
   let hasMore = $state(true);
@@ -309,6 +328,8 @@
         onOpenAlbumFolder={onOpenAlbumFolder}
         onReDownloadAlbum={onReDownloadAlbum}
         onAddAlbumToPlaylist={onAddAlbumToPlaylist}
+        onAlbumFavorite={(id) => { void toggleAlbumFavorite(id); }}
+        isAlbumFavorite={isFav}
         {downloadStateVersion}
         {isAlbumDownloaded}
         {showRanking}