Added material to the BeyondFacts Lab (#1180)

app/MindWork AI Studio/Assistants/BeyondFactsLab/BflMaterialKind.cs

@@ -0,0 +1,24 @@
+namespace AIStudio.Assistants.BeyondFactsLab;
+
+/// <summary>
+/// What a material of the BeyondFacts Lab came from, which decides how the lab keeps it and how it reaches a model.
+/// </summary>
+public enum BflMaterialKind
+{
+    /// <summary>
+    /// A document, e.g., a paper or slides: the lab keeps its text. Also every material stored before the lab knew
+    /// other kinds.
+    /// </summary>
+    DOCUMENT = 0,
+
+    /// <summary>
+    /// An audio or video recording: the lab keeps the text of its transcript.
+    /// </summary>
+    RECORDING,
+
+    /// <summary>
+    /// An image, e.g., a poster: the lab keeps a copy prepared for models, which goes along with every message to a
+    /// model which can see images.
+    /// </summary>
+    IMAGE,
+}