Let the tool calling loop stream what each round produces

app/MindWork AI Studio/Tools/ToolCallingSystem/Harness/ToolCallingRound.cs

@@ -1,10 +1,14 @@
 namespace AIStudio.Tools.ToolCallingSystem.Harness;
 
 /// <summary>
-/// The outcome of one non-streamed round of a tool calling conversation, in a shape that no
-/// longer depends on the provider API it came from.
+/// The outcome of one round of a tool calling conversation, in a shape that no longer depends on
+/// the provider API it came from.
 /// </summary>
-/// <param name="TextOutput">The text the model produced, empty when it only requested tool calls.</param>
+/// <param name="TextOutput">
+/// The text the model produced, empty when it only requested tool calls. The loop reads this to
+/// tell an answered round from a silent one; it does not show it, because the very same text has
+/// already reached the user as deltas while the round was running.
+/// </param>
 /// <param name="Calls">The tool calls the model requested, empty when it answered instead.</param>
 /// <param name="Sources">Sources the provider itself attached, such as those of a provider-native web search.</param>
 public sealed record ToolCallingRound(string TextOutput, IReadOnlyList<ToolCallingRequestedCall> Calls, IReadOnlyList<ISource> Sources);