feat: add inital in memory dispatcher

Add a simple in memory dispatcher for scalar requests and stream request.

src/request.tests/_fixtures/AmbiguousScalarHandler.cs

@@ -0,0 +1,19 @@
+// Copyright (c) The Geekeey Authors
+// SPDX-License-Identifier: EUPL-1.2
+
+namespace Geekeey.Request.Tests;
+
+public class AmbiguousScalarHandler : IScalarRequestHandler<AmbiguousScalarRequest, string>
+{
+	// Public method with the same name and signature
+	public Task<string> HandleAsync(AmbiguousScalarRequest request, CancellationToken ct)
+	{
+		return Task.FromResult("Public-Handled");
+	}
+
+	// Explicit interface implementation
+	Task<string> IScalarRequestHandler<AmbiguousScalarRequest, string>.HandleAsync(AmbiguousScalarRequest request, CancellationToken ct)
+	{
+		return Task.FromResult("Interface-Handled");
+	}
+}