Linter-contributed improvements:
- EnsureCentralService() method: registers Central's own domain as a
service from config, with cleanup on domain change
- Tests for EnsureCentralService: registration, idempotency, domain
change cleanup, no-domain-is-noop
- Improved reconciliation tests with Central as a registered service
- Certbot handler cleanup
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Paul Payne
c18217944f