v5.4.1 — Private Test Track

Behind the wall this release: the crew built a private test track. Every full systems check now runs on a disposable copy of the garage — spun up fresh, driven hard, torn down after — instead of taking turns on the shared floor. Checks that used to wait on each other now run together, so what took half an hour takes minutes, and nothing a test does can ever touch the real shelves. Nothing changes on your side of the counter — this one's for the crew.