feat: create request projects for basic CQRS

src/request.dispatcher.tests/_fixtures/roslyn/BuilderNestedHandler.cs

@@ -0,0 +1,18 @@
+using System.Threading;
+using System.Threading.Tasks;
+
+using Geekeey.Request.Dispatcher;
+
+namespace Sample;
+
+public sealed class Ping : IScalarRequest<string>
+{
+}
+
+public sealed class Container
+{
+	public sealed class PingHandler : IScalarRequestHandler<Ping, string>
+	{
+		public Task<string> HandleAsync(Ping request, CancellationToken cancellationToken) => Task.FromResult("pong");
+	}
+}