Refactor domain layer to follow Clean Architecture

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.

ECMJobRunner.Domain/Interfaces/IProfileSqlJobRepository.cs

@@ -0,0 +1,12 @@
+using ECMJobRunner.Domain.Entities;
+
+namespace ECMJobRunner.Domain.Interfaces
+{
+    /// <summary>
+    /// Repository interface for ProfileSqlJob entity
+    /// </summary>
+    public interface IProfileSqlJobRepository : IRepository<ProfileSqlJob>
+    {
+        // Add custom ProfileSqlJob-specific methods here if needed
+    }
+}