Two correlation invariants real Chrome holds were missing, so the
nav Response was never attached to goto().
requestId === loaderId for the main Document event. Both clients
gate isNavigationRequest() on this; we were emitting a synthetic
per-page id.
Network.requestWillBeSent for the Document fires before
Page.frameNavigated. Playwright's FrameManager needs the request
present as pendingDocument before the frame commits, otherwise
currentDocument lands with request=undefined.
Subresource events and the Document's responseReceived /
loadingFinished stay where they were.
Verified end-to-end on both clients against example.com (200),
google.com (200), httpbin/404 (404).