Issue #3614379: Declare Drupal 12 compatibility, because the pinned core requirement makes every dependent unable to resolve a next-major lane

Widens core_version_requirement to ^11.3 || ^12 in all six info files (the module, kessai_simulator, kessai_audit_trail, kessai_worldline, kessai_views and the test module) and updates the README requirements line to match.

The next-major jobs are run on this branch and read before the widening is claimed; findings and fixes are pushed here.