Fix: Handle empty PORT env var with default value 7860

Dockerfile

@@ -47,5 +47,5 @@ HEALTHCHECK --interval=30s --timeout=10s --start-period=40s --retries=3 \
     CMD curl --fail http://localhost:${PORT:-7860}/_stcore/health || exit 1
 
 # Run Streamlit app using PORT env var from Hugging Face Spaces
-# HuggingFace sets $PORT, don't override it.
-CMD ["bash", "-c", "streamlit run app.py --server.address=0.0.0.0 --server.port=$PORT --server.headless=true"]
+# HuggingFace sets $PORT, don't override it. Default to 7860 if not set.
+CMD ["bash", "-c", "streamlit run app.py --server.address=0.0.0.0 --server.port=${PORT:-7860} --server.headless=true"]

app.py

@@ -7,9 +7,8 @@ from llm import chat, set_model
 from model_config import MODEL_CHOICES, MODEL_TO_PROVIDER
 
 # Configure Streamlit for Hugging Face Spaces
-# Use PORT env var if provided (Hugging Face Spaces sets this), otherwise default to 7860
-port = os.getenv("PORT", "7860")
-os.environ["STREAMLIT_SERVER_PORT"] = port
+# Port is set via command line argument in Dockerfile
+# Don't set STREAMLIT_SERVER_PORT here to avoid conflicts
 os.environ["STREAMLIT_SERVER_ADDRESS"] = "0.0.0.0"