feat: implement docker infrastructure (US-001)

- Add docker-compose.yml with postgres, redis, api, and web services
- Add multi-stage Dockerfile for API (Python 3.11)
- Add multi-stage Dockerfile for web (Node.js 20 + nginx)
- Add Makefile with common development commands
- Add .env.example with all required environment variables
- Add placeholder pyproject.toml and package.json for builds
- Configure health checks for all services
- Setup persistent volumes for postgres, redis, and repos
- Run services as non-root users

apps/api/.dockerignore

@@ -1,15 +0,0 @@
-__pycache__/
-*.py[cod]
-*$py.class
-*.so
-.venv/
-venv/
-ENV/
-env/
-*.egg-info/
-dist/
-build/
-.git/
-.env
-.env.local
-*.log