Add initial ASP.NET Core project structure

This commit introduces the initial setup for the DigitalData.TaskFlow solution:
- Added `DigitalData.TaskFlow.sln` to organize the project structure into `src`, `presentation`, `core`, and `infrastructure` folders.
- Created `DigitalData.TaskFlow.API` project targeting .NET 8.0 with nullable reference types and Swagger/OpenAPI support.
- Added `Program.cs` to configure the ASP.NET Core application with services, middleware, and Swagger UI.
- Added `launchSettings.json` for development profiles and environment variables.
- Added `appsettings.json` and `appsettings.Development.json` for logging and configuration.

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

@@ -0,0 +1,25 @@
+var builder = WebApplication.CreateBuilder(args);
+
+// Add services to the container.
+
+builder.Services.AddControllers();
+// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
+builder.Services.AddEndpointsApiExplorer();
+builder.Services.AddSwaggerGen();
+
+var app = builder.Build();
+
+// Configure the HTTP request pipeline.
+if (app.Environment.IsDevelopment())
+{
+    app.UseSwagger();
+    app.UseSwaggerUI();
+}
+
+app.UseHttpsRedirection();
+
+app.UseAuthorization();
+
+app.MapControllers();
+
+app.Run();