Provide Docker containerization

[jeisaacs]

Summary

Create Docker images (or docker-compose setup) to run the full stack with minimal host dependencies.

Why

• Simplifies onboarding for contributors without Python/Node installed
• Enables consistent deployments across environments
• Paves the way for hosting on container platforms

Proposal

• Author multi-stage Dockerfiles for backend + frontend, plus docker-compose for local dev
• Include healthcheck, volume mounts for data, and env var configuration
• Document workflows for development vs. production images

Acceptance Criteria

• docker compose up starts the app with both services communicating
• Images follow best practices (small base, non-root where possible)
• README/docs explain how to override ports and persistence
• CI (future) can build/test the images