Names real technology throughout (Vault, Authentik, pfSense,
firewalld, Wazuh) instead of staying generic, adds a 'why this
approach vs the alternative' section to every doc, cross-links
heavily between docs instead of treating each system in isolation.
Completes the docs/ set - all 16 systems now have a full deep-dive
page in the diagram+callout+table style. Architecture overview covers
the 4 trust boundaries and 2 traffic planes; IaC pipeline is a fresh
Packer->Terraform->Ansible writeup replacing the stale old-content/
snapshot; disaster recovery covers the 3 independent backup layers
and the deliberately decoupled OS/app upgrade systems.