~anthropic/claude-sonnet-latest → B (70:30)

Side B introduces a substantive architectural change (SSE-based fetch pipeline with oneshot result signaling, structured FetchJobResult states, new fetch module, extensive tracing, and JS SSE consumer) that fixes a real UX gap (async fetch feedback) and is validated by an updated integration test. Side A is a small, focused UI grouping fix with a good regression test, but it's much narrower in scope and impact compared to B's cross-cutting feature work despite B's Cargo.lock noise and unrelated docstring removals.