Added tool calling support (#731)

Co-authored-by: krut_ni <nils.kruthoff@dlr.de>
Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Provider/OpenAI/ResponsesFunctionCallItem.cs

@@ -0,0 +1,15 @@
+namespace AIStudio.Provider.OpenAI;
+
+/// <summary>
+/// A function call item returned by the OpenAI Responses API.
+/// </summary>
+public sealed record ResponsesFunctionCallItem
+{
+    public string? Type { get; init; }
+
+    public string? CallId { get; init; }
+
+    public string? Name { get; init; }
+
+    public string? Arguments { get; init; }
+}