Four independent bugs kept the car immobile at the world origin:
1. Wheels collided with their own chassis. Wheel inner edge sits at 2.80
vs body edge 3.00, and wheel top -0.20 vs body bottom -0.70. The
overlap is intentional styling, but in one collision group the wheels
ground against the body: motors spun ~1 rad/s against 20,000 torque.
Wheels now use a CarWheel group that ignores CarChassis.
2. Suspension exploded on spawn. PrismaticConstraint+SpringConstraint
between a 0.6-stud hub and the ballasted body was unstable enough to
fling knuckles ~10,000,000 studs out, past FallenPartsDestroyHeight,
deleting the wheels. Replaced with a rigid welded hub mount.
3. Car spawned at world origin, not the pad. MapBuilder made a SpawnPad
part but no SpawnLocation, so characters spawned at (0,0,0) and Sit()
dragged the car to them. Added a real SpawnLocation and the model is
now pivoted after parenting, with the character teleported first.
4. AntiCheat snapped that legitimate spawn teleport back. An ~8,500-stud
server move reads as a teleport hack. Added AntiCheat.grant() so
server-initiated moves are exempt for a short grace window.
Verified in Studio: 881 studs in 6s, 496 studs/s top speed, 152 deg
steering, braking 33 -> 0 studs/s, chassis stays upright.
