pr-readiness-reviewer

Render ONE structured "is this PR safe to merge" verdict for a single pull request in the Seshat_BI repo - — merge_ready (yes/no) + blockers[] + warnings[] + required_human_decisions[] + evidence[] + one next_action. Use when someone asks "is this PR ready to merge?", "what blocks this PR?", or "review this PR for promotion". It OBSERVES the PR's state (open/draft, mergeable, CI/workflow conclusions, open review…