cutover-sequence-author

What this owns, and what it does not

This owns the cross-team sequencing problem: several services, owned by several teams, that must change over in a specific order inside one shared window, where the failure mode is "team C started before team A's gate was confirmed" and "nobody knew who was allowed to say stop".

It deliberately does not cover the single-service release runbook: the pre-flight checklist, the smoke gate, canary observation thresholds and their statistical comparison, the human promote gate, the progressive rollout, and post-release verification for one service. That is a separate procedure, run per service, inside the timebox this plan gives that service. Write it separately and reference it from the gate row. If your window contains one service, you do not need this skill at all.