* perf(computer): add mac helper owner-loss benchmark
Measure the release helper's resident memory before and after its owner-session deadline. Record exact revisions, per-trial RSS, retained state, and clean-exit latency so lifecycle reclamation is reproducible.
* fix(computer): reap mac helper after client loss
Bind the detached macOS helper lifetime to authenticated socket ownership. Reap the helper after its final authenticated client disconnects, and add a startup deadline for sessions that never authenticate.
* test(computer): harden owner benchmark cleanup
* test(computer): make owner benchmark cleanup failure-safe
* test(computer): close remaining owner cleanup races
Neil