Promote the 0.1.0-dev line to a stable release: raise the minimum Dart
SDK to ^3.13.0 and move betto_common and betto_abnf to their stable
^0.1.0 releases.

Also reformats two test files under the Dart 3.13 formatter, which
splits argument lists differently to 3.12.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>