Bounded producer/consumer pipeline

Implement process_all(items, transform, workers=3): - feed items through a queue.Queue into workers daemon threads - each worker applies transform(item) and collects results thread-safely - process_all must RETURN (not hang) once every item is processed, returning sorted(results) - a worker that forgets task_done() deadlocks the join — make sure you call it exactly once per item, even when transform raises is NOT required here (transform is assumed safe)

Difficulty: advanced