Fixed classic RAG sending more passages than the model can take (#1168)

app/MindWork AI Studio/Tools/RAG/PassageSelection.cs

@@ -0,0 +1,9 @@
+namespace AIStudio.Tools.RAG;
+
+/// <summary>
+/// Which passages of the classic RAG process fit into its budget, see PassageBudget.SelectAsync.
+/// </summary>
+/// <param name="Contexts">The passages which fit, grouped by data source in the order the data sources came in, and within a data source in the order of their rank. A passage which had to be shortened is here in its shorter form.</param>
+/// <param name="PassageCounts">How many passages of each data source fit, in the order the data sources came in.</param>
+/// <param name="LeftOutCount">How many passages did not fit.</param>
+public sealed record PassageSelection(IReadOnlyList<PreparedRetrievalContext> Contexts, IReadOnlyList<int> PassageCounts, int LeftOutCount);