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/ModelComparisonSeriesDataSources.cs

@@ -0,0 +1,16 @@
+using AIStudio.Settings.DataModel;
+
+namespace AIStudio.Assistants.ModelComparison;
+
+/// <summary>
+/// The data sources both chats of a comparison series may search, and how they search them.
+/// </summary>
+/// <param name="DataSourceIds">The IDs of the data sources.</param>
+/// <param name="RetrievalMode">How both chats search them, or null without any data source.</param>
+public readonly record struct ModelComparisonSeriesDataSources(IReadOnlyList<string> DataSourceIds, DataSourceRetrievalMode? RetrievalMode)
+{
+    /// <summary>
+    /// No data source at all.
+    /// </summary>
+    public static readonly ModelComparisonSeriesDataSources NONE = new([], null);
+}