~anthropic/claude-sonnet-latest → A (3:2)

Side A fixes a real semantic bug (silently defaulting to index 0 via unwrap_or, masking mismatches) with an explicit invariant-asserting expect, removes an inconsistent conditional link-hiding UI branch, and adds targeted regression tests plus doc corrections across three files. Side B is a reasonable UI simplification/dedup (removing a redundant toolbar action) but is more of a cleanup/refactor with less correctness impact and no new test coverage.