Raise the floor past CVE-2024-12797-affected wheels (43.x / 44.0.0).
Add constraints.txt (exact 44.0.1) and requirements.lock.txt with
sha256 hashes for cryptography and its runtime deps.
Permanent revoke and rekey retired the live pubkey without retaining it,
so historical checkpoints and off-box anchors became permanently
unverifiable. Add append-only agent_keys (public material only); retire
on revoke/rekey; verify against the fingerprint-named historical key.
Document a dedicated checkpoint-signer identity in the runbook.
Add requirements.txt (cryptography>=43.0.0,<45) and docs/PROD_RUNBOOK.md
requiring SIGIL_SEAL_PASS and SIGIL_ANCHOR on separate storage. Document
info findings R9/R12/R13 in DESIGN; leave R10 domain separation as a
versioned follow-up (not backward-safe).
