refactor(api): make audio tagging and decryption async to avoid UI blocking

src/lib/services/deezer/downloader.ts

@@ -81,6 +81,7 @@ export async function downloadTrack(
     const reader = response.body!.getReader();
     const chunks: Uint8Array[] = [];
     let downloadedBytes = 0;
+    let lastReportedPercentage = 0;
 
     while (true) {
       const { done, value } = await reader.read();
@@ -89,15 +90,19 @@ export async function downloadTrack(
       chunks.push(value);
       downloadedBytes += value.length;
 
-      // Call progress callback
+      // Call progress callback every 5%
       if (onProgress && totalSize > 0) {
         const percentage = (downloadedBytes / totalSize) * 100;
-        console.log(`[Download Progress] ${downloadedBytes}/${totalSize} bytes (${percentage.toFixed(1)}%)`);
-        onProgress({
-          downloaded: downloadedBytes,
-          total: totalSize,
-          percentage
-        });
+        const roundedPercentage = Math.floor(percentage / 5) * 5;
+
+        if (roundedPercentage > lastReportedPercentage || percentage === 100) {
+          lastReportedPercentage = roundedPercentage;
+          onProgress({
+            downloaded: downloadedBytes,
+            total: totalSize,
+            percentage
+          });
+        }
       }
     }
 
@@ -111,20 +116,23 @@ export async function downloadTrack(
 
     console.log(`Downloaded ${encryptedData.length} bytes, encrypted: ${isCrypted}`);
 
+    // Yield to the browser to keep UI responsive
+    await new Promise(resolve => setTimeout(resolve, 0));
+
     // Decrypt if needed
     let decryptedData: Uint8Array;
 
     if (isCrypted) {
-      console.log('Decrypting track using Rust...');
+      console.log('Decrypting track...');
       // Use the provided decryption track ID (for fallback tracks) or the original track ID
-      const trackIdForDecryption = decryptionTrackId || track.id.toString();
+      const trackIdForDecryption = decryptionTrackId ? decryptionTrackId.toString() : 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),
+      // Call Rust decryption function - Tauri returns Vec<u8> as number[]
+      const decryptedArray = await invoke<number[]>('decrypt_deezer_track', {
+        data: encryptedData,
         trackId: trackIdForDecryption
       });
-      decryptedData = new Uint8Array(decrypted);
+      decryptedData = new Uint8Array(decryptedArray);
     } else {
       decryptedData = encryptedData;
     }

src/lib/services/deezer/tagger.ts

@@ -90,14 +90,12 @@ export async function tagAudioFile(
 ): Promise<void> {
   const metadata = convertToTaggingMetadata(track);
 
-  // Convert Uint8Array to regular array for JSON serialization
-  const coverArray = coverData ? Array.from(coverData) : undefined;
-
+  // Tauri handles Uint8Array -> Vec<u8> conversion automatically
   try {
     await invoke('tag_audio_file', {
       path: filePath,
       metadata,
-      coverData: coverArray,
+      coverData,
       embedLyrics,
     });
   } catch (error) {