Make the local-only void-exp rootfs useful as a dev VM baseline by baking Docker and Compose into the XBPS package set instead of leaving container setup to manual follow-up.
Enable the docker runit service during image assembly, add a small boot preflight that loads the needed netfilter/overlay modules and applies the Docker sysctl file before dockerd starts, and keep the Void cleanup path removing caches, docs, and stale get-docker artifacts.
Refresh the README and repo guidance to describe Docker as part of the current Void image contract and to remind users that they need to rebuild and recreate Void VMs to pick it up.
Verified with bash -n make-rootfs-void.sh and git diff --check for the touched files. I did not run a live make rootfs-void or boot a fresh Void VM in this pass.
Make iterating on a Firecracker-friendly Void guest practical without replacing the Debian default image path.
Add local Void rootfs build/register/verify plumbing, a language-agnostic dev package baseline, and guest SSH/work-disk hardening so new images use the runtime bundle key, keep a normal root bash environment, and repair stale nested /root layouts on restart.
Replace the guest PING/PONG responder with an HTTP /healthz agent over vsock, rename the runtime bundle and config surface from ping helper to agent while still accepting the legacy keys, and route the post-SSH reminder through the new vm.health path.
Validated with GOCACHE=/tmp/banger-gocache go test ./..., make build, bash -n customize.sh make-rootfs-void.sh, and git diff --check.
