Playwright must own the spawn (it needs the inspection pipe), but
hermes desktop is not just build+launch - stamp checks, integrity
gates, sandbox fixups, and a constructed child environment. So the
driver intercepts the product's own launch: a sitecustomize.py on
PYTHONPATH (opt-in via HERMES_E2E_CAPTURE_LAUNCH) wraps subprocess.run,
captures argv/cwd/env at the spawn site, and fakes success instead of
spawning; launch-from-spec.mjs then _electron.launch-es exactly that
spec and clicks Settings -> About -> Update now. Completion is product
state, not a Playwright event: the handoff result file or the checkout
reaching the expected sha (source installs write no result file).
Ships with the driver, so it works unchanged on every sampled OLD ref
- no product flag, no pre-flag fallback split. Both launch shapes are
matched (npm exec electron / packaged exe under apps/desktop/release);
npm BUILD calls pass through untouched. Exit 0 without a capture fails
the leg: a version that never reached its launch must not pass.
Probe-the-probe: scripts/launch_capture_probe.sh runs control rows
(no opt-in, non-launch argv) and both treatment shapes - all green
locally. Gate flips on the shared run workflow for linux/macos;
windows adopts the same path with the driver restructuring.
