Stream the tool calling rounds of the Responses API

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

@@ -0,0 +1,13 @@
+namespace AIStudio.Provider.OpenAI;
+
+/// <summary>
+/// The closing line of a streamed Responses API call, which repeats the whole response.
+/// </summary>
+/// <remarks>
+/// Everything the round produced comes back here, reasoning items included, in the same shape a
+/// non-streamed call would have returned. That is why a streamed tool calling round needs no
+/// reassembly: this line is the round.
+/// </remarks>
+/// <param name="Type">The type of the stream event.</param>
+/// <param name="Response">The response as a non-streamed call would have returned it.</param>
+public sealed record ResponsesCompletedStreamLine(string Type, ResponsesResponse? Response);