Add Docker support for local development #60

Summary

Add Docker support so the project can be built and run consistently in a containerized environment.

Proposed changes

• Add a Dockerfile
• Add a .dockerignore
• Update the README with Docker build/run steps

Why this helps

• Makes setup easier for new contributors
• Improves reproducibility across systems
• Supports local development and demo runs

Notes

I am working on this as a contribution for the project.