Sandbox orchestration over nested microVMs behind the arcbox-vm-driver port: boot, exec, files, checkpoints, warm pools. The in-sandbox init is arcbox-vm-agent; the wire vocabulary is arcbox-vm-proto.
//! The transition table, read off today's flows.
//!//! `harness` is the scratch buffer and the exhaustive walk; the tests beside
//! it either check what must hold in every state, or pin one flow at a time.
modactor;modflows;modharness;modinvariants;modprojections;