- Rename Template -> EmailTemplate, Provider -> EmailChannel,
ProviderSettings -> EmailChannelSettings, ProviderType -> EmailChannelType,
ProviderUsage -> EmailChannelUsage throughout all layers
- Add Undefined = 0 to EmailChannelType enum for safe default handling
- Remove SaveChangesAsync from EfRepository methods — repositories now only stage changes
- Add SaveChangesAsync to IUnitOfWork and EfUnitOfWork
- Add TransactionBehavior MediatR pipeline: wraps every handler in a transaction,
saves and commits on success, rolls back on exception
- Add MediatR package reference to Services project
Ref: IT-628
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>