~anthropic/claude-sonnet-latest → B (6:4)

Side B fixes a concrete correctness/security bug (feed catch-up using ingest position instead of timestamp, preventing missed posts on clock rollback and leaked private-room content after permission changes) and backs it with thorough multi-user integration tests. Side A is a solid internal-tooling refactor (per-commit vs per-author ranking with rollup) but addresses a fairness/design limitation rather than a user-facing correctness bug, making B's impact more concrete and durable.