Add test infrastructure and repository tests

Introduced `CfgProfileDto` for testing and added a `FakeDataGenerator` utility for generating test data. Updated `ECMJobRunner.Tests.csproj` to support both `.NET Framework 4.8` and `.NET 8.0`, enabling nullable reference types and adding dependencies for testing frameworks, DI, and AutoMapper.

Added `TestFixture` to set up dependency injection and in-memory databases for tests. Created `TestMappingProfile` for AutoMapper configurations. Implemented `CfgProfileRepositoryTests` to validate repository methods, including `GetByIdAsync`, `GetAllAsync`, `AddAsync`, and `FindAsync`.

Enhanced test maintainability with `FluentAssertions` and realistic data generation using `Bogus`.

ECMJobRunner.Tests/DTOs/CfgProfileDto.cs

@@ -0,0 +1,20 @@
+using System;
+
+namespace ECMJobRunner.Tests.DTOs
+{
+    /// <summary>
+    /// DTO for CfgProfile entity used in tests
+    /// </summary>
+    public class CfgProfileDto
+    {
+        public bool Active { get; set; }
+        public string ProfileName { get; set; } = string.Empty;
+        public byte TypeId { get; set; }
+        public string? Schedule { get; set; }
+        public string? Comment { get; set; }
+        public string AddedWho { get; set; } = string.Empty;
+        public DateTime AddedWhen { get; set; }
+        public string ChangedWho { get; set; } = string.Empty;
+        public DateTime ChangedWhen { get; set; }
+    }
+}