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/ModelComparisonModelKey.cs

@@ -0,0 +1,35 @@
+using AIStudio.Provider;
+
+namespace AIStudio.Assistants.ModelComparison;
+
+/// <summary>
+/// What tells one model apart from another across stored comparisons, see ModelComparisonModelIdentity.
+/// </summary>
+/// <param name="LLMProvider">The kind of provider which ran the model.</param>
+/// <param name="Hostname">The address of the server of a self-hosted model in lowercase, without a trailing slash; empty for every other provider.</param>
+/// <param name="ModelId">The ID of the model at its provider.</param>
+public readonly record struct ModelComparisonModelKey(LLMProviders LLMProvider, string Hostname, string ModelId) : IComparable<ModelComparisonModelKey>
+{
+    /// <summary>
+    /// Gets the key of a model, with its host written the same way however the user typed it.
+    /// </summary>
+    /// <param name="llmProvider">The kind of provider which ran the model.</param>
+    /// <param name="hostname">The address of the server of a self-hosted model, or empty.</param>
+    /// <param name="modelId">The ID of the model at its provider.</param>
+    /// <returns>The key.</returns>
+    public static ModelComparisonModelKey Of(LLMProviders llmProvider, string hostname, string modelId) => new(llmProvider, hostname.Trim().TrimEnd('/').ToLowerInvariant(), modelId);
+
+    /// <summary>
+    /// Orders keys the same way on every computer, so that a pair of models is always written in the same order.
+    /// </summary>
+    /// <param name="other">The other key.</param>
+    public int CompareTo(ModelComparisonModelKey other)
+    {
+        var byProvider = this.LLMProvider.CompareTo(other.LLMProvider);
+        if (byProvider != 0)
+            return byProvider;
+
+        var byHost = string.CompareOrdinal(this.Hostname, other.Hostname);
+        return byHost != 0 ? byHost : string.CompareOrdinal(this.ModelId, other.ModelId);
+    }
+}