No Dockerfile — harder to integrate into CI pipelines #46

Blast Radius has no Dockerfile, making it harder to use in CI pipelines (GitLab CI, GitHub Actions) where Orbit may not be available.

Recommendation: Add a multi-stage Dockerfile that:

1. Installs orbit CLI (if publicly available)
2. Installs blast-radius via pip
3. Provides an entrypoint for blast-radius <path>
   This enables docker run in any CI pipeline without installing Orbit on the runner.