feat(download): add download button to playlist view and album download button

- Add download functionality to PlaylistDetailView (track-by-track)
- Add handleDisplayTrackDownload handler for playlist tracks
- Add "Download Album" button to AlbumDetailView header actions
- handleDownloadAlbum queues all non-downloaded tracks for download

src/lib/components/views/AlbumDetailView.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
   import { onMount } from 'svelte';
   import { invoke } from '@tauri-apps/api/core';
-  import { ArrowLeft, Play, Shuffle, Heart, Plus, MoreHorizontal } from 'lucide-svelte';
+  import { ArrowLeft, Play, Shuffle, Heart, Plus, MoreHorizontal, Download } from 'lucide-svelte';
   import TrackRow from '../TrackRow.svelte';
   import { getDownloadState, type DownloadStatus } from '$lib/stores/downloadState';
 
@@ -51,6 +51,7 @@
     onTrackDownload?: (track: Track) => void;
     onTrackRemoveDownload?: (trackId: number) => void;
     getTrackDownloadStatus?: (trackId: number) => { status: DownloadStatus; progress: number };
+    onDownloadAlbum?: () => void;
   }
 
   let {
@@ -71,7 +72,8 @@
     onAddTrackToPlaylist,
     onTrackDownload,
     onTrackRemoveDownload,
-    getTrackDownloadStatus
+    getTrackDownloadStatus,
+    onDownloadAlbum
   }: Props = $props();
 
   let currentTrack = $state<number | null>(null);
@@ -186,6 +188,11 @@
         <button class="icon-btn" onclick={onAddToQueue}>
           <Plus size={20} color="white" />
         </button>
+        {#if onDownloadAlbum}
+          <button class="icon-btn" onclick={onDownloadAlbum} title="Download album">
+            <Download size={20} color="white" />
+          </button>
+        {/if}
         <button class="icon-btn">
           <MoreHorizontal size={20} color="white" />
         </button>

src/lib/components/views/PlaylistDetailView.svelte

@@ -4,6 +4,7 @@
   import { open } from '@tauri-apps/plugin-dialog';
   import { onMount } from 'svelte';
   import TrackRow from '../TrackRow.svelte';
+  import { type DownloadStatus } from '$lib/stores/downloadState';
 
   interface PlaylistTrack {
     id: number;
@@ -71,6 +72,9 @@
     onTrackShareSonglink?: (track: DisplayTrack) => void;
     onTrackGoToAlbum?: (albumId: string) => void;
     onTrackGoToArtist?: (artistId: number) => void;
+    onTrackDownload?: (track: DisplayTrack) => void;
+    onTrackRemoveDownload?: (trackId: number) => void;
+    getTrackDownloadStatus?: (trackId: number) => { status: DownloadStatus; progress: number };
   }
 
   let {
@@ -84,7 +88,10 @@
     onTrackShareQobuz,
     onTrackShareSonglink,
     onTrackGoToAlbum,
-    onTrackGoToArtist
+    onTrackGoToArtist,
+    onTrackDownload,
+    onTrackRemoveDownload,
+    getTrackDownloadStatus
   }: Props = $props();
 
   let playlist = $state<Playlist | null>(null);
@@ -494,6 +501,7 @@
       </div>
 
       {#each displayTracks as track, idx (track.id)}
+        {@const downloadInfo = getTrackDownloadStatus?.(track.id) ?? { status: 'none' as const, progress: 0 }}
         <TrackRow
           number={idx + 1}
           title={track.title}
@@ -501,7 +509,11 @@
           duration={track.duration}
           quality={track.hires ? 'Hi-Res' : undefined}
           isFavorite={favoriteTrackIds.has(track.id)}
+          downloadStatus={downloadInfo.status}
+          downloadProgress={downloadInfo.progress}
           onPlay={() => handleTrackClick(track)}
+          onDownload={onTrackDownload ? () => onTrackDownload(track) : undefined}
+          onRemoveDownload={onTrackRemoveDownload ? () => onTrackRemoveDownload(track.id) : undefined}
           menuActions={{
             onPlayNow: () => handleTrackClick(track),
             onPlayNext: onTrackPlayNext ? () => onTrackPlayNext(track) : undefined,

src/routes/+page.svelte

@@ -1004,12 +1004,69 @@
     }
   }
 
+  async function handleDownloadAlbum() {
+    if (!selectedAlbum) return;
+
+    const tracksToDownload = selectedAlbum.tracks.filter(track => {
+      const status = getDownloadState(track.id).status;
+      return status === 'none' || status === 'failed';
+    });
+
+    if (tracksToDownload.length === 0) {
+      showToast('All tracks already downloaded', 'info');
+      return;
+    }
+
+    showToast(`Downloading ${tracksToDownload.length} tracks from "${selectedAlbum.title}"`, 'info');
+
+    for (const track of tracksToDownload) {
+      try {
+        await downloadTrack({
+          id: track.id,
+          title: track.title,
+          artist: track.artist || selectedAlbum.artist || 'Unknown',
+          album: selectedAlbum.title,
+          albumId: selectedAlbum.id,
+          durationSecs: track.durationSeconds,
+          quality: track.quality || 'CD Quality',
+          bitDepth: track.bitDepth,
+          sampleRate: track.samplingRate,
+        });
+      } catch (err) {
+        console.error(`Failed to queue download for "${track.title}":`, err);
+      }
+    }
+  }
+
   function getTrackDownloadStatus(trackId: number) {
     // Access downloadStateVersion to trigger reactivity
     void downloadStateVersion;
     return getDownloadState(trackId);
   }
 
+  async function handleDisplayTrackDownload(track: PlaylistTrack) {
+    try {
+      const quality = track.hires && track.bitDepth && track.samplingRate
+        ? `${track.bitDepth}bit/${track.samplingRate}kHz`
+        : 'CD Quality';
+      await downloadTrack({
+        id: track.id,
+        title: track.title,
+        artist: track.artist || 'Unknown',
+        album: track.album,
+        albumId: track.albumId,
+        durationSecs: track.durationSeconds,
+        quality,
+        bitDepth: track.bitDepth,
+        sampleRate: track.samplingRate,
+      });
+      showToast(`Downloading "${track.title}"`, 'info');
+    } catch (err) {
+      console.error('Failed to start download:', err);
+      showToast('Failed to start download', 'error');
+    }
+  }
+
   function handleDisplayTrackPlayNext(track: PlaylistTrack) {
     queueTrackNext(buildQueueTrackFromDisplayTrack(track));
   }
@@ -1532,6 +1589,7 @@
           onTrackDownload={handleTrackDownload}
           onTrackRemoveDownload={handleTrackRemoveDownload}
           getTrackDownloadStatus={getTrackDownloadStatus}
+          onDownloadAlbum={handleDownloadAlbum}
         />
       {:else if activeView === 'artist' && selectedArtist}
         <ArtistDetailView
@@ -1568,6 +1626,9 @@
           onTrackShareSonglink={(track) => shareSonglinkTrack(track.id, track.isrc)}
           onTrackGoToAlbum={handleAlbumClick}
           onTrackGoToArtist={handleArtistClick}
+          onTrackDownload={handleDisplayTrackDownload}
+          onTrackRemoveDownload={handleTrackRemoveDownload}
+          getTrackDownloadStatus={getTrackDownloadStatus}
         />
       {:else if activeView === 'favorites'}
         <FavoritesView