Fixed Semantic Search with external data sources (ERI servers) (#1090)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

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

@@ -12,6 +12,9 @@ public sealed class RetrievalTextContext : IRetrievalContext
     
     /// <inheritdoc />
     public required RetrievalContentCategory Category { get; init; }
+
+    /// <inheritdoc />
+    public string SourceCategory { get; init; } = string.Empty;
     
     /// <inheritdoc />
     public required RetrievalContentType Type { get; init; }