Headless Chromium at scale: four fixes for a fleet that kept eating RAM

The first time a worker died with an OOM kill in the middle of a render, I assumed it was a bad page — some site with an infinite-scroll loop or a 200MB hero video. The second time it happened, on a different worker rendering a different URL, I started paying attention. The third time, a Tuesday morning, every worker in the fleet went down inside a five-minute window. Headless Chromium leaks memory. Not in a "oh that's a bug, file an issue" way — in a "this is the operating reality of a 30-milli