- resolveOwnerScopedSessionKey's getOwners in the Python and JS executors
only read live sessions, so a subagent reset issued while the shared
kernel was still starting resolved to the base key, awaited the
parent's startup, and shut its brand-new kernel down.
- Python and JS starting sessions are now owner-bearing records like
Ruby/Julia's: owners attach synchronously before startup resolves,
getOwners and per-owner disposal consult them, and the final
sessions.set is identity-guarded so a disposed starting record cannot
resurrect its kernel.
- Regression: deferred PythonKernel.start proves a concurrent subagent
reset forks immediately and never reaps the parent's starting kernel
(fails with the previous getOwners).
can1357
4d45e8154a