Fixed attached files silently reaching the AI as empty documents (#904)

app/MindWork AI Studio/Tools/FileExtractionOutcome.cs

@@ -0,0 +1,23 @@
+namespace AIStudio.Tools;
+
+/// <summary>
+/// How reading a file ended.
+/// </summary>
+public enum FileExtractionOutcome
+{
+    /// <summary>
+    /// The whole file was read.
+    /// </summary>
+    SUCCESS,
+
+    /// <summary>
+    /// Parts of the file could not be read, e.g. single pages of a PDF, while the remaining
+    /// content is still usable.
+    /// </summary>
+    PARTIAL,
+
+    /// <summary>
+    /// The file could not be read. There is no content the app is allowed to use.
+    /// </summary>
+    FAILED,
+}