86a04d2d34
The old gate ran firefox --headless --screenshot, which renders fine even when the juggler automation layer is missing from the package — so a binary Playwright can't actually drive (firefox-8) passed and shipped broken. Replace it with a real drive gate: a 5-leg matrix that launches each binary over the juggler pipe on its native runner, loads a page, and round-trips JS (also asserts navigator.webdriver stays hidden). Headless and no screenshot, so it stays GPU-free on the hosted runners and needs no proxy or secrets. Same logic is reusable standalone via verify-assets.yml to drive-test an existing release's assets without a rebuild.