First secure Linux deployment

Rookhold's strong boundary requires a dedicated Linux x86_64 VM, cgroup v2, the pinned gVisor runtime, a private root filesystem, and a scoped credential.

ROOKHOLD_PRODUCTION_VM_ACKNOWLEDGED=true scripts/bootstrap-production.sh

The acknowledgement does not make a general-purpose Docker host safe. The outer service is privileged so it can create one isolated gVisor workload per job. Follow the complete deployment guide and do not accept untrusted work until every production check passes.