The `SaveChangesAsync` method was removed from the `IRepository`
interface in the `ECMJobRunner.Domain.Interfaces` namespace.
This method previously allowed saving all changes asynchronously
with an optional `CancellationToken` parameter.
Updated the domain layer to align with Clean Architecture principles:
- Removed Entity Framework dependencies from the project.
- Updated AGENTS.md to document the new architecture.
- Introduced repository interfaces for data access abstraction.
- Added a generic IRepository interface for CRUD operations.
- Implemented entity-specific repositories for Profile, ProfileSqlJob, and ProfileHistory.
- Ensured the domain layer is infrastructure-independent with pure POCOs.
- Updated project structure and documentation for clarity.
