Added the Model Comparison assistant for blind comparisons of two models (#1009)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Assistants/ModelComparison/ModelComparisonParticipant.cs

@@ -0,0 +1,22 @@
+namespace AIStudio.Assistants.ModelComparison;
+
+/// <summary>
+/// One of the two models in a comparison, and the way to ask it.
+/// </summary>
+/// <remarks>
+/// The way to ask is a function rather than a provider, so the comparison itself does not depend on
+/// anything of the app. ModelComparisonProviderAdapter builds the function for a real
+/// provider.
+/// </remarks>
+public sealed record ModelComparisonParticipant
+{
+    /// <summary>
+    /// The name to show for the model. It is copied into the answer, see ModelComparisonAnswer.Label.
+    /// </summary>
+    public required string Label { get; init; }
+
+    /// <summary>
+    /// Sends a prompt to the model and streams the answer back, chunk by chunk.
+    /// </summary>
+    public required Func<string, CancellationToken, IAsyncEnumerable<string>> Ask { get; init; }
+}