A green CI run proves only that a particular PR head passed against the environment and base

A green CI run proves only that a particular PR head passed against the environment and base context exercised at that time; it does not prove the PR remains merge-ready after the base branch advances. For long-lived or repeatedly synchronized PRs, re-check the live head/base SHAs, mergeability, and overlapping base changes immediately before handoff or merge. This limit matters most when another feature edits the same validation or UI integration seams; it is less relevant when the base is unchanged.