The orchestration test polls for the fixture's readiness marker with
existsSync and then reads the PID. The fixture published the marker with
a single writeFileSync, so a child descheduled between the internal open
and write exposed a zero-byte file; Number('') is 0 and process.kill(0, 0)
probes the caller's process group, so the protected ESRCH assertion failed
with "Missing expected exception" while the production SIGKILL plus
awaited-close teardown had demonstrably worked.
Publish through a staging file and renameSync, the same atomic pattern
as the blocker() fixture in credential-helper.test.ts, so a reader that
sees the marker always sees the complete owned PID. Assertions, poll
budget, timeout and production behavior are unchanged; negative controls
in the task triage report show broken kill or broken awaited-close still
fail the protected assertion.
Signed-off-by: Logan Johnson <loganj@squareup.com>
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