Fix: Add missing backend/services module with SpotifyService and cache

backend/services/__init__.py

@@ -0,0 +1 @@
+# Services Package

backend/services/cache.py

@@ -0,0 +1,4 @@
+# Cache Service - Re-export CacheManager from backend.cache_manager
+from backend.cache_manager import CacheManager
+
+__all__ = ['CacheManager']

backend/services/spotify.py

@@ -0,0 +1,19 @@
+# Spotify Service - Placeholder for YouTube Music API interactions
+# Currently uses yt-dlp directly in routes.py
+
+class SpotifyService:
+    """
+    Placeholder service for Spotify/YouTube Music integration.
+    Currently, all music operations are handled directly in routes.py using yt-dlp.
+    This class exists to satisfy imports but has minimal functionality.
+    """
+    def __init__(self):
+        pass
+    
+    def search(self, query: str, limit: int = 20):
+        """Search for music - placeholder"""
+        return []
+    
+    def get_track(self, track_id: str):
+        """Get track info - placeholder"""
+        return None