Feature: extract embedded cover art from audio files to display as thumbnails

backend/workers/thumbnails.go

@@ -91,6 +91,8 @@ func (m *ThumbnailManager) worker(id int) {
 			err = generateImageThumbnail(fullSourcePath, destPath)
 		} else if strings.HasPrefix(job.MimeType, "video/") {
 			err = generateVideoThumbnail(fullSourcePath, destPath)
+		} else if strings.HasPrefix(job.MimeType, "audio/") {
+			err = generateAudioThumbnail(fullSourcePath, destPath)
 		} else if strings.HasSuffix(job.FilePath, ".docx") || strings.HasSuffix(job.FilePath, ".pptx") || strings.HasSuffix(job.FilePath, ".xlsx") {
 			err = generateOfficeThumbnail(job.FilePath, destPath, m.Config)
 		} else {
@@ -135,6 +137,25 @@ func generateVideoThumbnail(src, dest string) error {
 	return nil
 }
 
+func generateAudioThumbnail(src, dest string) error {
+	// Extract embedded cover art from audio file, scale to 256x256
+	cmd := exec.Command("ffmpeg", "-y", "-i", src, "-an", "-vcodec", "mjpeg", "-vframes", "1", "-vf", "scale=256:256:force_original_aspect_ratio=decrease", dest)
+	
+	timer := time.AfterFunc(10*time.Second, func() {
+		if cmd.Process != nil {
+			cmd.Process.Kill()
+		}
+	})
+	
+	err := cmd.Run()
+	timer.Stop()
+	
+	if err != nil {
+		return fmt.Errorf("ffmpeg audio cover extraction failed: %w", err)
+	}
+	return nil
+}
+
 func generateOfficeThumbnail(filePath, destPath string, cfg *config.Config) error {
 	// Generate a download token for the Conversion API to fetch the file from our backend
 	token, err := middleware.GenerateDownloadToken(0, "system_worker", cfg.JWTSecret)

frontend/src/components/FileExplorer.tsx

@@ -1173,7 +1173,8 @@ export default function FileExplorer({ onLogout }: FileExplorerProps) {
     const isImage = ['jpg', 'jpeg', 'png', 'gif', 'webp', 'svg'].includes(ext) || file.mime_type?.startsWith('image/');
     const isVideo = ['mp4', 'mkv', 'avi', 'mov', 'webm', 'ogg'].includes(ext) || file.mime_type?.startsWith('video/');
     const isOffice = ['docx', 'doc', 'pptx', 'ppt', 'xlsx', 'xls'].includes(ext) || file.mime_type?.includes('officedocument');
-    const isMedia = isImage || isVideo || isOffice;
+    const isAudio = ['mp3', 'flac', 'wav', 'm4a', 'wma', 'aac'].includes(ext) || file.mime_type?.startsWith('audio/');
+    const isMedia = isImage || isVideo || isOffice || isAudio;
 
     if (ext === 'pdf') {
       return (