Fix: Importar 'services' y 'cache_manager' en main.py

backend/main.py

@@ -11,8 +11,12 @@ from dotenv import load_dotenv
 # Cargar variables de entorno desde .env
 load_dotenv()
 
+import services
+from cache_manager import start_background_refresh, cache_stats
+
 app = FastAPI(title="Dashboard Leads API", version="1.0")
 
+
 # Orígenes CORS configurables (por defecto permite todo o el dominio configurado)
 cors_env = os.getenv("CORS_ORIGINS", "*")
 origins = [o.strip() for o in cors_env.split(",") if o.strip()] if cors_env != "*" else ["*"]