Added a retrieval context validation agent (#289)

app/MindWork AI Studio/Agents/RetrievalContextValidationResult.cs

@@ -0,0 +1,12 @@
+using AIStudio.Tools.RAG;
+
+namespace AIStudio.Agents;
+
+/// <summary>
+/// Represents the result of a retrieval context validation.
+/// </summary>
+/// <param name="Decision">Whether the retrieval context is useful or not.</param>
+/// <param name="Reason">The reason for the decision.</param>
+/// <param name="Confidence">The confidence of the decision.</param>
+/// <param name="RetrievalContext">The retrieval context that was validated.</param>
+public readonly record struct RetrievalContextValidationResult(bool Decision, string Reason, float Confidence, IRetrievalContext? RetrievalContext) : IConfidence;