All base images (debian:bookworm-slim, ubuntu:22.04, ubuntu:20.04,
rockylinux:9-minimal, centos:7, alpine:3.19, fedora:39,
kalilinux/kali-rolling, archlinux:latest, honeynet/conpot:latest)
now carry their resolved sha256 digest so 'docker pull' is
deterministic. :tag retained for human readability; @sha256 is what
Docker actually resolves. Refresh procedure documented at the top of
decnet/distros.py.
topology_id[:8] appeared twice with no explanation. 8 chars is the
git short-SHA convention; collision-safe within a single deployment's
network namespace.
