feat: add base entity abstractions and domain model to DAL.Abstract
- IEntity<TId>, Entity<TId>, Entity base classes in Entities/
- Template, TemplateVariable domain models in Templates/
- Provider, ProviderSettings, SmtpProviderSettings, ProviderUsage, ProviderType in Providers/
- ITemplateRepository, IProviderRepository, IProviderUsageRepository in Repositories/
- ProviderUsage tracks daily counts; monthly derived by summing daily records
- IEntity<TId> lives in DAL.Abstract (not DAL.EF) — boundary enforced from the start
Ref: IT-628
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Anatolii Grynchuk
7cb691db14