Add DI setup for modular architecture

Introduced `DependencyInjection.cs` in Application and Infrastructure layers to centralize service registration. Updated project files to include necessary package references (`Microsoft.Extensions.Configuration.Abstractions` and `Microsoft.Extensions.DependencyInjection.Abstractions`) and project dependencies between layers. Integrated service registration in `Program.cs` to enable modular architecture for the API.

src/presentation/DigitalData.TaskFlow.API/DigitalData.TaskFlow.API.csproj

@@ -14,4 +14,9 @@
     <Folder Include="Controllers\" />
   </ItemGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\..\core\DigitalData.TaskFlow.Application\DigitalData.TaskFlow.Application.csproj" />
+    <ProjectReference Include="..\..\infrastructure\DigitalData.TaskFlow.Infrastructure\DigitalData.TaskFlow.Infrastructure.csproj" />
+  </ItemGroup>
+
 </Project>

src/presentation/DigitalData.TaskFlow.API/Program.cs

@@ -1,6 +1,12 @@
+using DigitalData.TaskFlow.Application;
+using DigitalData.TaskFlow.Infrastructure;
+
 var builder = WebApplication.CreateBuilder(args);
+var config = builder.Configuration;
 
 // Add services to the container.
+builder.Services.AddApplicationServices(config);
+builder.Services.AddInfrastructureServices(config);
 
 builder.Services.AddControllers();
 // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle