Added transcription of audio and video files to local data sources (#1081)

Co-authored-by: Paul Koudelka <106623909+PaulKoudelka@users.noreply.github.com>

app/MindWork AI Studio/Provider/TranscriptionResult.cs

@@ -1,8 +1,17 @@
 namespace AIStudio.Provider;
 
-public sealed record TranscriptionResult(bool Success, string Text, string ErrorMessage = "")
+/// <summary>
+/// What a transcription provider answered.
+/// </summary>
+/// <param name="Success">Whether the provider returned a transcript.</param>
+/// <param name="Text">The transcript.</param>
+/// <param name="ErrorMessage">Why the transcription failed, for the user, when it is known.</param>
+/// <param name="FileRejected">Whether the provider refused the media file itself, so that it would refuse the same file again.</param>
+public sealed record TranscriptionResult(bool Success, string Text, string ErrorMessage = "", bool FileRejected = false)
 {
     public static TranscriptionResult FromText(string text) => new(true, text);
 
     public static TranscriptionResult Failure(string errorMessage = "") => new(false, string.Empty, errorMessage);
+
+    public static TranscriptionResult Rejection(string errorMessage) => new(false, string.Empty, errorMessage, true);
 }