ci-poller ci-ready handoff

Preserve the deliberate handoff: remove stale ci-ready, revalidate the exact approved snapshot, remove ci-pending, then always add fresh ci-ready to trigger publishing. Trap: treating the add as infallible or idempotent looks simpler, but a failed add strands the issue outside polling. Fix: restore ci-pending; if restoration also fails, revoke accepted, ci-pending, and ci-ready fail-closed.