A late self-cancel can arrive after the RPC service nursery has
closed. Starting `Actor.cancel()` there raises before teardown can
cancel the shielded parent-channel loop or run lifetime callbacks.
Schedule one root-owned task to await `Actor.cancel(None)` before
cancelling the root scope. Deduplicate pending requests, and cancel
the root scope directly once runtime cancellation has completed.
Add a fresh-child regression for open and closed service nurseries
under native Trio and asyncio infection. Check repeated requests
before completion, after completion and from a lifetime callback;
prove all three creator-owned shm segments disappear before parent
nursery teardown can mask a failure. Include the session raw record
referenced by the structured provenance already in the parent.
Prompt-IO:
ai/prompt-io/opencode/20260916_ib_disconnect_cleanup.md
(this patch was generated in some part by `opencode`
using `gpt-6-astra` (`openai`))
Gud Boi