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/ModelComparisonQuestionPreview.cs

@@ -0,0 +1,30 @@
+namespace AIStudio.Assistants.ModelComparison;
+
+/// <summary>
+/// Shortens a question to what a summary or a stored result keeps of it, so that the user recognizes it again.
+/// </summary>
+public static class ModelComparisonQuestionPreview
+{
+    /// <summary>
+    /// How many characters of a question the Model Comparison assistant keeps at most.
+    /// </summary>
+    public const int MAX_CHARACTERS = 300;
+
+    /// <summary>
+    /// Shortens a question, and marks the cut.
+    /// </summary>
+    /// <param name="question">The question.</param>
+    /// <param name="maxCharacters">The number of characters of the question to keep, at most.</param>
+    /// <returns>The question, or its beginning followed by an ellipsis.</returns>
+    public static string Of(string question, int maxCharacters = MAX_CHARACTERS)
+    {
+        ArgumentOutOfRangeException.ThrowIfNegativeOrZero(maxCharacters);
+
+        if (question.Length <= maxCharacters)
+            return question;
+
+        // Cutting between the two halves of a character outside the basic plane, an emoji for example, would leave half of it:
+        var length = char.IsHighSurrogate(question[maxCharacters - 1]) ? maxCharacters - 1 : maxCharacters;
+        return question[..length].TrimEnd() + "…";
+    }
+}