~anthropic/claude-sonnet-latest → B (85:15)

Side B is a substantive type-safety refactor that threads a CanonicalItemUrl newtype through pair selection, validation, and rank-change computation, eliminating repeated string-to-key conversions and reducing risk of mismatched string comparisons, plus adds Deref impls with a test. Side A is a trivial one-line UI tweak (conditionally omitting disabled=false) with no lasting architectural value.