The themes were renamed to shipaurora/borealis and shipaurora/minimal, and
Packagist no longer finds the old names, so no version of the CMS could be
installed. The CMS now requires shipaurora/borealis, and its docs and
comments name the themes by their new names and repositories.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>