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

Side B implements a real functional improvement (SSE-based async entity fetch with proper job result tracking, rate-limit handling, and updated JS/client integration plus adjusted integration test), delivering concrete new user-facing behavior. Side A is a large but purely mechanical type-renaming/relocation refactor (moving string helpers into newtypes) with no behavior change and even removes some test coverage duplicated elsewhere, offering less lasting functional value despite its size.