Initial infrastructure mono-repo scaffold

Consolidates nixos, docker, raspi, and debian-configuration into a single
infrastructure-as-code repo. Includes:

- ansible/: full inventory + proxmox-hardening, freeipa, and raspberrypi
  roles (converted from debian-configuration bash scripts)
- terraform/: Proxmox VMs, Dynu DNS, Pi-hole (decommissioned stub),
  Docker container catalog — migrated from docker/infrastructure/terraform/
- stacks/docker/, stacks/raspi/, nixos/: placeholder READMEs pending
  git subtree population (see implementation plan)
- docs/: internal MkDocs site with architecture, network topology, runbooks,
  and drift-detection guide; external sanitized site
- scripts/: drift-detect.sh, docs-build.sh, install-hooks.sh, check-secrets.sh
- CI: secret-scan (push/PR), drift-detect (daily), docs-build (on change)
- Pi-hole removed throughout — DNS is FreeIPA, DHCP is router

See docs/internal/implementation-plan.md for the phased rollout after
pushing to Gitea.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UvNjoxTWEDkhXsd1Dq2ETP

ansible/roles/proxmox-hardening/defaults/main.yml

@@ -0,0 +1,22 @@
+---
+# proxmox-hardening role defaults.
+# Override in inventory/group_vars/proxmox.yml or host_vars/<host>/vars.yml.
+
+proxmox_harden_ssh: true
+proxmox_configure_firewall: true
+proxmox_configure_unattended_upgrades: true
+proxmox_switch_to_nosub_repo: true
+proxmox_disable_nag: true
+proxmox_setup_ipa_sudo: true
+
+# Management CIDR for the PVE datacenter firewall (inbound allow-list).
+# Must be set per-host in inventory (hosts.yml) — no default here to force explicit assignment.
+# proxmox_mgmt_cidr: "192.168.2.0/24"
+
+# Named PVE admin username to create (set to "" to skip user creation).
+# proxmox_admin_username: "wayne"
+
+# fail2ban sshd jail settings
+proxmox_fail2ban_maxretry: 5
+proxmox_fail2ban_bantime: "1h"
+proxmox_fail2ban_findtime: "10m"