Phased plan to take Plane-2 from clarify+plan to producing reviewable draft PRs:
locked decisions (GitHub App pull-requests:write, zero-AWS, read-only box), the
mandatory gates (/sh-plan-review + /sh-security-review + GPT-4.1 cross-review on
the CI surface), the B4 CI trust boundary (split CI, denylist, diff-hash, pure-code
green gate), phases 0-6 with owners + exercised rollbacks, what changes vs what
does not, risks, and definition of done. Input to /sh-plan-review before any build.
