Promotion Boundary. The lifecycle line that separates prepared review evidence from accountable state change. A promotion boundary lets systems, reviewers, and AI assistants assemble evidence, surface risks, and recommend readiness, but reserves review -> stable, release approval, exception acceptance, and other consequential promotions for the human authority named by the process.
The release approval boundary is the publishing form of the same line: generated release artifacts can prepare the decision, but not cross it.