Wrap the documented publisher stream in `try/finally` and explicitly
cancel its `start_actor()` daemon. Closing `open_stream_from()` owns
only the remote stream task, so actor-nursery exit otherwise waits on
the still-running actor indefinitely.
Review: PR #484 (OpenCode)
https://github.com/goodboy/tractor/pull/484#pullrequestreview-5025383596
(this patch was generated in some part by `opencode` using `gpt-5.6-sol` (`openai`))