fix(home): reactively update offline cache state in Continue Listening

Include downloadStateVersion in the each loop key to force re-render
when offline cache state changes, fixing tracks showing gray icons
even when cached.

src/lib/components/views/HomeView.svelte

@@ -837,7 +837,7 @@
             <h2>{$t('home.continueListening')}</h2>
           </div>
           <div class="track-list compact">
-            {#each continueTracks as track, index}
+            {#each continueTracks as track, index (`${track.id}-${downloadStateVersion}`)}
               {@const isActiveTrack = isPlaybackActive && activeTrackId === track.id}
               {@const isTrackDownloaded = checkTrackDownloaded?.(track.id) || false}
               <TrackRow