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

docs/internal/runbooks/proxmox-hardening.md

@@ -0,0 +1,52 @@
+# Runbook: Proxmox VE Hardening
+
+Applies Stage 1 hardening to a fresh Proxmox VE node using the `proxmox-hardening` Ansible role.
+
+## Pre-conditions
+
+- Fresh PVE install with root SSH access
+- SSH key already added to root's `authorized_keys`
+- Host added to `ansible/inventory/hosts.yml` under the `proxmox` group
+
+## Steps
+
+```bash
+# 1. Verify connectivity
+cd ansible
+ansible-playbook playbooks/ping.yml --limit <hostname>
+
+# 2. Dry-run to preview changes
+ansible-playbook playbooks/proxmox.yml --limit <hostname> --check --diff
+
+# 3. Review the diff output, then apply
+ansible-playbook playbooks/proxmox.yml --limit <hostname>
+
+# 4. Verify hardening state
+ansible-playbook playbooks/proxmox.yml --limit <hostname> --tags audit --check
+```
+
+## What gets applied
+
+1. **APT repos** — enterprise source disabled, no-subscription source enabled
+2. **SSH hardening** — `PermitRootLogin prohibit-password`, `PasswordAuthentication no`, fail2ban
+3. **Datacenter firewall** — default-deny inbound; SSH (22) and web UI (8006) from management CIDR only
+4. **Unattended upgrades** — security-only origins, no auto-reboot
+5. **Named admin user** — `<proxmox_admin_username>@pve` with Administrator role (one-time)
+6. **IPA sudo** — `admins` group gets NOPASSWD sudo for shell and PVE tools
+7. **Subscription nag** — cosmetic patch to remove the nag dialog
+
+## Variables to set per-host
+
+In `ansible/inventory/hosts.yml`:
+```yaml
+pve1.sweet.home:
+  proxmox_mgmt_cidr: "192.168.2.0/24"
+  proxmox_admin_username: wayne
+```
+
+## After hardening
+
+- Log into the PVE web UI as the named admin, change the initial password
+- Enable TOTP/2FA for both the named admin and root@pam
+- Verify with the audit script: `cd /home/wayne/repos/debian-configuration && proxmox/scripts/audit.sh`
+  (will migrate to an Ansible audit task in a future iteration)