- Move registration marker interfaces to Registration/Abstractions
- Add feature folders with Abstractions subfolders: EffectiveConfig,
Dnsmasq/Config, Dnsmasq/Hosts, Dnsmasq/Leases, Dnsmasq/Reload,
Logs, Updates, UI/Settings, Common/Process
- Place interfaces in each feature's Abstractions namespace; align
implementation namespaces to folder paths
- Update Program, extensions, controllers, hubs, helpers, components,
and tests to use new namespaces
- Remove old flat Services/Abstractions and root-level service files
