Delete (archive) a policy group. A deployed group cannot be deleted (P-020); undeploy it first with lexq_deploy_undeploy, which also ends a running A/B test. This cannot be undone. The group no longer appears in lexq_groups_list and its name can be reused right away. Calls that change it (settings, versions, rules, starting an A/B test, publish, deploy, rollback, scheduling a deployment) return 409 P-059. If it was ever executed, deployed, or replayed, it is kept for audit; otherwise it is permanently deleted after 30 days.