Added the visual briefing assistant (#893)

app/MindWork AI Studio/Tools/Media/MediaImportOwnerKindExtensions.cs

@@ -0,0 +1,19 @@
+namespace AIStudio.Tools.Media;
+
+/// <summary>Capabilities of a media-import owner kind.</summary>
+public static class MediaImportOwnerKindExtensions
+{
+    /// <summary>
+    /// Gets whether the owner stores its own source list and transcripts.
+    /// </summary>
+    /// <remarks>
+    /// Owners that persist their own sources take the attached media over immediately and keep it
+    /// next to the stored document, see <see cref="MediaImportOwnerKind.VISUAL_BRIEFING"/>. The
+    /// attachment control must therefore neither wait for the transcription to finish before showing
+    /// the file, nor deliver the completed transcripts back into its own list afterwards, because
+    /// the owner already holds them. All other owners rely on that delivery instead.
+    /// </remarks>
+    /// <param name="kind">The owner kind to look up.</param>
+    /// <returns><c>true</c> when the owner persists its own sources.</returns>
+    public static bool PersistsOwnSources(this MediaImportOwnerKind kind) => kind is MediaImportOwnerKind.VISUAL_BRIEFING;
+}