Added a way to read what the AI received from your sources (#1100)

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

app/MindWork AI Studio/Chat/FileVersion.cs

@@ -0,0 +1,24 @@
+namespace AIStudio.Chat;
+
+/// <summary>
+/// The state of a file which a text was read from, to tell whether the file changed since.
+/// </summary>
+/// <remarks>
+/// The size counts as well as the time: some file systems keep the time coarsely, e.g., FAT to two
+/// seconds, and a network drive may report the time of another clock.
+/// </remarks>
+/// <param name="LastWriteUtc">When the file was last written.</param>
+/// <param name="Length">The size of the file in bytes.</param>
+public sealed record FileVersion(DateTime LastWriteUtc, long Length)
+{
+    /// <summary>
+    /// Reads the state of a file as it is now.
+    /// </summary>
+    /// <param name="filePath">The path of the file.</param>
+    /// <returns>The state, or null when the file is gone.</returns>
+    public static FileVersion? Of(string filePath)
+    {
+        var file = new FileInfo(filePath);
+        return file.Exists ? new(file.LastWriteTimeUtc, file.Length) : null;
+    }
+}