remove HF import

app.py

@@ -4,7 +4,6 @@ from app_claude import demo as demo_claude
 from app_fireworks import demo as demo_fireworks
 from app_gemini import demo as demo_gemini
 from app_groq import demo as demo_groq
-from app_hf import demo as demo_hf
 from app_hyperbolic import demo as demo_hyperbolic
 from app_mistral import demo as demo_mistral
 from app_nvidia import demo as demo_nvidia