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/ResponsesFunctionCallOutputItem.cs

@@ -0,0 +1,13 @@
+namespace AIStudio.Provider.OpenAI;
+
+/// <summary>
+/// A local function result item sent back to the OpenAI Responses API.
+/// </summary>
+public sealed record ResponsesFunctionCallOutputItem
+{
+    public string Type { get; init; } = "function_call_output";
+
+    public string CallId { get; init; } = string.Empty;
+
+    public string Output { get; init; } = string.Empty;
+}