2cd06814e6
Each Firecracker bottle created its run dir (holding an ~1G rootfs.ext4) but never removed it — launch teardown only terminated the VM. Every run leaked its rootfs, filling the CI runner's disk (187 stale sandbox-tester dirs / 141G in one incident). Register a run-dir rmtree callback on the ExitStack before the vm.terminate callback so, LIFO, the VM is gone before its rootfs is removed. ignore_errors keeps teardown resilient. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>