Containerize Application via Dockerfile

[Copilot]

Adds Docker containerization for deployment and reproducible dev environments.

Changes

• Dockerfile: Python 3.11-slim base, non-root user, curl for healthcheck
• Health endpoint: /health/ via HealthCheckAPIView with swagger docs
• Production server: gunicorn with 4 workers, 2 threads
• Healthcheck: --fail flag for proper status detection, 10s interval/start-period
• Entrypoint: Conditional collectstatic in DEBUG mode only (migrations handled separately)
• Security: DEBUG-only admin/swagger/static serving in urls.py

HEALTHCHECK --interval=10s --timeout=3s --start-period=10s --retries=3 \
  CMD ["curl", "--silent", "--fail", "http://localhost:8000/health/"]

ENTRYPOINT ["/app/entrypoint.sh"]
CMD ["--bind", "0.0.0.0:8000", "--workers", "4", "--threads", "2"]

Test coverage added for health endpoint.

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[Copilot]

Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details.

[hepheir]

변경 사항이 없는 PR. 인상깊게 봤습니다.

[hepheir]

지금 보니 세션상에는 LGTM이 달려있네요 👍