Hit both today doing a live QA pass on the gateway: plain
nixpkgs#chromium has no color-emoji font (tofu boxes read exactly
like a missing-icon bug), and a page whose content loads async after
the initial paint (SSE, fetch-on-mount) screenshots as a bare
"loading..." placeholder without --virtual-time-budget. Neither is a
real product bug, but both need a documented fix for when an accurate
render actually matters, not just "know to discount it."
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