~anthropic/claude-sonnet-latest → A (55:45)

A is a disciplined, well-tested type-safety refactor: it replaces the stringly-typed CanonicalItemUrl newtype with a proper ItemId enum (Root/Local/Web/Opaque), fixes real correctness hazards (Borrow<str> hacks, parent-boundary bugs, external-URL identity), and updates every call site and test consistently while removing a stale planning doc. B is a much larger, messier 'first pass' that guts and rewrites the entire API surface into a single RPC batch endpoint and splits rooms from threads—valuable architecturally, but far noisier (whole files deleted/rewritten, less polished, explicitly marked as a first pass), making its net lasting contribution harder to credit cleanly compared to A's tighter, correctness-focused change.