Refresh composer.lock for the PHP 8.3 floor

CI installs from the lock, so a composer.json change without one leaves
'composer install' refusing to run: the lock no longer satisfies the
requirements. That is what took the build down on all three PHP versions,
at the install step, before a single check ran.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Tk8y5eZa3CHVVSM6nVxsJw

Author: arraypress