Let the host ask the guest vsock agent to run ss so open ports can be surfaced without SSHing in manually.
Add a narrow /ports agent endpoint, a daemon vm.ports RPC that enriches listeners with <hostname>.vm endpoints and best-effort HTTP links, and a concurrent 'banger vm ports' CLI table for one or more VMs.
Update the guest package contract to include ss for rebuilt Debian images, allow the guest agent package in the shell-out policy, and cover the new parsing/RPC/CLI flow in tests.
Verified with GOCACHE=/tmp/banger-gocache go test ./... outside the sandbox, make build, bash -n customize.sh make-rootfs-void.sh verify.sh, and ./banger vm ports --help.
Move the default guest package list into a repo manifest and record a hash beside built rootfs images so run/make-rootfs can warn when the docker-ready image is stale.
Switch the Firecracker launch path to a single sparse root overlay per VM instead of separate /home and /var disks, so many VMs can share the same base image while still installing packages under /var and working from /root.
Keep older images bootable by masking stale home.mount and var.mount units at boot, and scrub those obsolete fstab entries when customize.sh rebuilds an image. Verified with bash -n on the updated scripts; no live VM boot was run in this environment.
