fix(wip): add fallback format support for unavailable tracks

Add support for selecting a fallback audio format if the requested
track format is unavailable. Users can now choose to fall back
to MP3_320, MP3_128, or the highest available format, or opt to fail
if the requested format is not found. The queue manager and downloader
now fetch fresh track data just-in-time, handle dz fallback
parameters, and ensure the correct track ID is used for decryption.
Settings UI and store are updated to allow configuring the fallback format.

src/lib/services/deezer/downloader.ts

@@ -29,7 +29,8 @@ export async function downloadTrack(
   musicFolder: string,
   format: string,
   onProgress?: ProgressCallback,
-  retryCount: number = 0
+  retryCount: number = 0,
+  decryptionTrackId?: string
 ): Promise<string> {
   // Generate paths
   const paths = generateTrackPath(track, musicFolder, format, false);
@@ -87,10 +88,13 @@ export async function downloadTrack(
 
     if (isCrypted) {
       console.log('Decrypting track using Rust...');
+      // Use the provided decryption track ID (for fallback tracks) or the original track ID
+      const trackIdForDecryption = decryptionTrackId || track.id.toString();
+      console.log(`Decrypting with track ID: ${trackIdForDecryption}`);
       // Call Rust decryption function
       const decrypted = await invoke<number[]>('decrypt_deezer_track', {
         data: Array.from(encryptedData),
-        trackId: track.id.toString()
+        trackId: trackIdForDecryption
       });
       decryptedData = new Uint8Array(decrypted);
     } else {
@@ -180,7 +184,7 @@ export async function downloadTrack(
       const errorType = isTimeout ? 'timeout' : error.code;
       console.log(`[DEBUG] Download ${errorType}, waiting 2s before retry (${retryCount + 1}/3)...`);
       await new Promise(resolve => setTimeout(resolve, 2000));
-      return downloadTrack(track, downloadURL, musicFolder, format, onProgress, retryCount + 1);
+      return downloadTrack(track, downloadURL, musicFolder, format, onProgress, retryCount + 1, decryptionTrackId);
     }
 
     throw error;