Keep a fully validated v1 primary authoritative over differing legacy recovery snapshots, recover missing or unusable v1 primaries from the best valid legacy candidate, and migrate the next mutation to v2 generation one.
Rebase prepared removals onto the current serialized keyring state so intervening creates survive, generations remain monotonic, and already absent targets complete idempotently.
Restrict canonical same-generation conflict blocking to true v2 documents and add separate legacy and v2 regression coverage without exposing key material.