#1023 get_jumper_client(queue_name=X) ignores X after the first call: spawns land on the process singleton's queue

Found while doing #916. engine/jumper_client.py get_jumper_client() is a process singleton; queue_name is used only on the first call. Callers that pass a different queue get the singleton's queue silently: engine/interpreters/inline_executor/execution_logging.py:138 get_jumper_client(queue_name="highway_internal") (async log tasks meant for the internal queue), engine/services/workflow_submission_service.py:141 get_jumper_client(queue_name=queue) when no jumper_client is passed (submissions to a non-default queue). In #916 the new request_run_container_cleanup guarded on client.queue_name and the scratch-DB e2e failed with 'container cleanup runs only on highway_internal' when it used get_jumper_client; it now constructs JumperClient(queue_name='highway_internal') directly. Needs: either get_jumper_client keyed per queue, or callers construct JumperClient for an explicit queue; plus a test that a second call with another queue gets that queue.