OnFileSelectedAsync called TryLoadAsync with a null passphrase to peek
the manifest, but the outer `catch (Exception)` surfaced the expected
"Passphrase required for encrypted bundle" ArgumentException as a fatal
"Failed to read bundle" error -- blocking the user from ever advancing
to the passphrase step. Catch ArgumentException specifically and let
the wizard advance normally on the next click.
Joseph Doherty
f3a571b664