[chore:] file picker, but currently not using the file itself

MainWindow.axaml.cs

@@ -442,4 +442,21 @@ public partial class MainWindow : Window
         ExportUtility.ExportToCSV(file.Path.AbsolutePath);
 
     }
+
+    private async void MnuImpResult_OnClick(object? sender, RoutedEventArgs e)
+    {
+        // Hier importieren
+        var topLevel = GetTopLevel(this);
+        var file = await topLevel!.StorageProvider.OpenFilePickerAsync(new FilePickerOpenOptions
+        {
+            Title = "CSV-Datei laden",
+            SuggestedFileType = new FilePickerFileType(".csv-Datei")
+            {
+                Patterns = new[] { "*.csv" }
+            }
+            
+        });
+
+        if (file == null) return;
+    }
 }