* fix: handle get_open_port import across TRL versions TRL 0.29+ removed get_open_port from exports; fall back to importing directly from vllm.utils or vllm.utils.network_utils. * support DP with vllm and make generation_batch_size confifurable
* fix: handle get_open_port import across TRL versions TRL 0.29+ removed get_open_port from exports; fall back to importing directly from vllm.utils or vllm.utils.network_utils. * support DP with vllm and make generation_batch_size confifurable