GitLab

- Remove hello-service (use new-service.sh to create services)
- Add docker-compose.yml for local PostgreSQL + Redis
- Make PostgreSQL the default in template (no more memory.rs)
- Add migration/ directory to service template
- Update ARCHITECTURE.md to match current project state
- Update README.md with docker-compose workflow
- Clean up outdated comments referencing hello-service
- Simplify verbose template comments while keeping useful hints
- Fix new-service.sh fallback sed anchor (hello-service → default)
- Add sea-orm-migration to workspace dependencies