triage-pr

Take a pull request from draft + failing CI to merge-ready, in two phases, choosing the phase from the PR's draft state:

• Phase A — while the PR is a draft: inspect failing checks, pull GitHub Actions logs, and fix failures in PR scope only. Loop until CI is green or report blockers. Phase A runs unattended — no human gate except hard blockers.
• Phase B — after the PR is ready-for-review: wait for configured reviewers, verify-then-propose dispositions (Step 9), then follow references/phase-b-envelope.md or references/phase-b-unattended.md per humanEnvelope / --auto-apply. Bounded by maxReviewRounds.