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

Side B fixes real crashing bugs in test infrastructure (wrong str/split arity, wrong HttpExchange method calls, unguarded nil derefs, missing exception handling causing hangs) that were actually breaking E2E auth test runs. Side A is a mechanical refactor introducing Deref newtypes and threading CanonicalItemUrl through call sites, which is reasonable cleanup but lower-stakes than fixing a broken test harness that blocks CI signal.