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

B is a tight, correct bugfix: it replaces timestamp-based feed cutoffs with ingest-position anchors (fixing same-millisecond races and clock rollback) and adds permission-aware room visibility, backed by focused integration tests proving the exact failure modes it fixes. A vendors an entire new 'durable' crate wholesale—including marketing README, RFC docs, motivation.md, multiple examples, and a duplicated Cargo.lock—so most of its bulk is generated/boilerplate noise, with the actual server-side change (entity_store.rs, streaming replay) being comparatively small and unproven by tests for the RAM-reduction claim. Per the rubric favoring precise, necessary fixes over diffuse churn, B delivers more verified, lasting correctness per line changed.