Implements full-stack user functionality following layered architecture:
- User domain models and validation
- RESTful API endpoints (GET /users/{id}, POST /users)
- PostgreSQL database with migrations and indexes
- Repository pattern with interfaces
- Service layer with business logic
- Integration tests and error handling
- Docker Compose for local development

🤖 Generated with Claude Code

Co-Authored-By: Claude <noreply@anthropic.com>