Fix: Include backend/audio Django app in repository

backend/audio/urls.py

@@ -0,0 +1,46 @@
+"""Audio URL patterns"""
+
+from django.urls import path, include
+from rest_framework.routers import DefaultRouter
+from audio.views import (
+    AudioListView,
+    AudioDetailView,
+    AudioPlayerView,
+    AudioProgressView,
+    AudioDownloadView,
+)
+from audio.views_lyrics import LyricsViewSet, LyricsCacheViewSet
+
+# Create router for ViewSets
+router = DefaultRouter()
+router.register(r'lyrics', LyricsViewSet, basename='lyrics')
+router.register(r'lyrics-cache', LyricsCacheViewSet, basename='lyrics-cache')
+
+urlpatterns = [
+    # YouTube audio endpoints (specific paths first)
+    path('list/', AudioListView.as_view(), name='audio-list'),
+    path('<str:youtube_id>/player/', AudioPlayerView.as_view(), name='audio-player'),
+    path('<str:youtube_id>/progress/', AudioProgressView.as_view(), name='audio-progress'),
+    path('<str:youtube_id>/download/', AudioDownloadView.as_view(), name='audio-download'),
+    # Lyrics endpoints
+    path('<str:youtube_id>/lyrics/', LyricsViewSet.as_view({
+        'get': 'retrieve',
+        'put': 'update_lyrics',
+        'patch': 'update_lyrics',
+        'delete': 'delete_lyrics',
+    }), name='audio-lyrics'),
+    path('<str:youtube_id>/lyrics/fetch/', LyricsViewSet.as_view({
+        'post': 'fetch',
+    }), name='audio-lyrics-fetch'),
+    path('<str:youtube_id>/', AudioDetailView.as_view(), name='audio-detail'),
+    
+    # Include sub-apps LAST (they have root patterns that catch everything)
+    # Local audio endpoints
+    path('', include('audio.urls_local')),
+    # Quick Sync endpoints
+    path('', include('audio.urls_quick_sync')),
+    # Artwork and metadata endpoints
+    path('api/', include('audio.urls_artwork')),
+    # Include router URLs for batch operations
+    path('', include(router.urls)),
+]