New TurnKey SilverStripe version (19.0)

Changes:

• Install Silverstripe CMS 6.2.0 from its pinned official release tag and supported Composer patch channel.
• Restore firstboot administrator credentials, the public webroot, page and asset publishing, and MariaDB persistence on Debian 13 Trixie with PHP 8.4.
• Add a supervised Silverstripe update helper and focused v19 acceptance coverage.

Links

• Release meta-files (signature, manifest)