Added PowerPoint templates to the Slide Assistant (#1055)

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

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

@@ -0,0 +1,23 @@
+namespace AIStudio.Tools.PowerPoint;
+
+/// <summary>
+/// Something a slide of a template carries besides the placeholders of its layout, e.g., a picture
+/// or a text box its author placed by hand.
+/// </summary>
+/// <remarks>
+/// The model knows a template slide by the slots of its layout, which it fills. Everything else on
+/// the slide stays unless the model removes it, so the model learns what there is and where:
+/// a sample picture, a hint to name the source of a picture, or a chart in the way of a slot.
+/// </remarks>
+/// <param name="Number">The number of the element on its slide, starting at 1, from back to front; the model refers to it as "element 1".</param>
+/// <param name="ShapeId">The ID of the shape on the slide, which finds the element again when the presentation is written.</param>
+/// <param name="Kind">What kind of element it is.</param>
+/// <param name="Bounds">Where it sits on the slide; null when the file does not say.</param>
+/// <param name="Text">Its text, one paragraph per line; empty when it has none.</param>
+internal sealed record TemplateSlideElement(int Number, uint ShapeId, TemplateSlideElementKind Kind, SlotBounds? Bounds, string Text)
+{
+    /// <summary>
+    /// How the model refers to the element.
+    /// </summary>
+    public string Name => $"element {this.Number}";
+}