Add all RAG backend files - force add

Delete app/middleware/rate_limit.py with huggingface_hub

Delete app/middleware/auth.py with huggingface_hub

Delete app/middleware/__init__.py with huggingface_hub

Upload app/middleware/__init__.py with huggingface_hub

Upload app/middleware/rate_limit.py with huggingface_hub

Upload app/middleware/auth.py with huggingface_hub