Added PowerPoint templates to the Slide Assistant (#1055)

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

app/MindWork AI Studio/Tools/PowerPoint/LibraryPictures.cs

@@ -0,0 +1,14 @@
+namespace AIStudio.Tools.PowerPoint;
+
+/// <summary>
+/// The pictures of a picture library which a slide deck may use, by their numbers, which follow those of the pictures for the slides.
+/// </summary>
+/// <param name="Count">How many pictures of the library the LLM may choose from.</param>
+/// <param name="IconNumbers">The numbers of those which are icons.</param>
+internal sealed record LibraryPictures(int Count, IReadOnlySet<int> IconNumbers)
+{
+    /// <summary>
+    /// No library at all.
+    /// </summary>
+    public static readonly LibraryPictures NONE = new(0, new HashSet<int>());
+}