fix: configure uvicorn proxy headers for HuggingFace deployment

Configure uvicorn to properly handle proxy headers in HuggingFace Spaces
environment. This resolves "Invalid host header" errors caused by the
proxy infrastructure.

Changes:
- Add forwarded_allow_ips="*" to accept all proxy IPs
- Add proxy_headers=True to trust X-Forwarded-* headers
- Apply configuration to start_hf.py entry point used by HuggingFace

This ensures the backend correctly handles requests from the HuggingFace
Spaces proxy layer.

start_hf.py

@@ -34,5 +34,7 @@ if __name__ == "__main__":
         host=host,
         port=port,
         log_level="info",
-        reload=False
+        reload=False,
+        forwarded_allow_ips="*",  # Allow all proxy IPs for HuggingFace
+        proxy_headers=True  # Trust proxy headers from HuggingFace
     )