10 new tests: state field transitions (ready/suspended/dead), yield from nested helper function, initial resume arg ignored by ready coroutine, mutable closure state via dict-set!, complex yield values (list/dict), round-robin scheduling, factory creates independent coroutines, resuming non-coroutine raises error. 27/27 pass on both OCaml and JS. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>