Cover Settings gateways (Session, LoginPersistence, SystemAudit, Smtp,
FrontendTelemetry, Metadata, App), Auth gateways (ExternalIdentity,
Tenant), DirectorySettings, UserSettings, and HotkeyService.
Gateway test coverage rises from 25% to 52%, overall service/gateway
coverage from 58.6% to 70.7%.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
