Fix: Set PORT variable before using it in CMD

Dockerfile

@@ -50,4 +50,4 @@ HEALTHCHECK --interval=30s --timeout=10s --start-period=40s --retries=3 \
 # Run Streamlit app using PORT env var from Hugging Face Spaces
 # HuggingFace sets $PORT, don't override it. Default to 7860 if not set.
 # Try the main app now
-CMD ["bash", "-c", "echo Using PORT=${PORT:-7860} && streamlit run app.py --server.address=0.0.0.0 --server.port=${PORT:-7860}"]
+CMD ["bash", "-c", "PORT=${PORT:-7860} && echo Using PORT=$PORT && streamlit run app.py --server.address=0.0.0.0 --server.port=$PORT"]