Auto-create audio_library folder and improve scanner error handling

src/services/audioScanner.js

@@ -13,8 +13,25 @@ export class AudioScanner {
 
   async scanLibrary() {
     console.log(`🔍 Scanning library: ${this.libraryPath}`);
+    
+    // Check if directory exists, create if not
+    try {
+      await fs.access(this.libraryPath);
+    } catch (error) {
+      console.log(`📁 Creating library directory: ${this.libraryPath}`);
+      await fs.mkdir(this.libraryPath, { recursive: true });
+      console.log(`⚠️  Directory was empty. Add audio files to ${this.libraryPath} and scan again.`);
+      return;
+    }
+    
     const files = await this.findAudioFiles(this.libraryPath);
     console.log(`📁 Found ${files.length} audio files`);
+    
+    if (files.length === 0) {
+      console.log(`⚠️  No audio files found in ${this.libraryPath}`);
+      console.log(`   Add .mp3, .m4a, .flac, .wav, .aac, or .ogg files and scan again.`);
+      return;
+    }
 
     let processed = 0;
     for (const filePath of files) {