The orchestration layer never injected enabled_worker_ids into seed and
value nodes, so workers could not resolve their index and fell back to
returning the original seed unchanged.
- Remove DistributedListSplitter and DistributedListCollector nodes
- Remove /distributed/init_list_queue and /distributed/request_list_item endpoints
- Clean up all references from prompt_transform, queue_orchestration, constants, and tests
- Refactor and reorganize distributed modules for quality improvements