debug: Add file listing and use python -m streamlit

- Add ls command to debug file visibility
- Use python -m streamlit instead of direct streamlit command
- Troubleshoot 'No such file or directory' runtime error

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Dockerfile

@@ -39,6 +39,7 @@ USER root
 COPY . /home/app/
 COPY hello_world.py /home/app/app.py
 RUN chown -R app:app /home/app/
+RUN ls -la /home/app/  # Debug: list files to verify copy worked
 
 # Switch back to app user for runtime
 USER app
@@ -55,5 +56,5 @@ ENV STREAMLIT_BROWSER_GATHER_USAGE_STATS=false
 # Health check
 HEALTHCHECK CMD curl --fail http://localhost:7860/_stcore/health
 
-# Run Streamlit
-CMD ["streamlit", "run", "app.py", "--server.port=7860", "--server.address=0.0.0.0"]
+# Verify files exist and run Streamlit
+CMD ["sh", "-c", "ls -la /home/app/ && python -m streamlit run app.py --server.port=7860 --server.address=0.0.0.0"]