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/new-host.md

@@ -0,0 +1,59 @@
+# Runbook: Provisioning a New Host
+
+Steps for adding a new machine to the infrastructure.
+
+## NixOS host on Proxmox
+
+```bash
+# 1. Use the PXE boot menu or installer ISO
+#    The auto-installer at pxe-boot.sweet.home presents all flake targets.
+
+# 2. Add to nixos/ flake if a new build-type is needed
+#    Otherwise pick the closest existing target (e.g. proxmox-minimal)
+
+# 3. Add SSH host key to clan vars (enables SOPS decryption)
+cd nixos
+./scripts/sync-host-keys.sh <target>
+
+# 4. Create the VM/LXC via Terraform
+cd ../terraform/proxmox
+# Add a resource block in the appropriate .tf file
+terraform plan
+terraform apply
+
+# 5. Deploy NixOS
+nixos-rebuild switch --flake ./nixos#<target> --target-host <hostname>
+```
+
+## Non-NixOS host (Proxmox VM)
+
+```bash
+# 1. Create VM in Proxmox (manually or via terraform)
+# 2. Add to ansible/inventory/hosts.yml with correct group
+# 3. Add SSH key, verify connectivity:
+ansible-playbook ansible/playbooks/ping.yml --limit <hostname>
+# 4. Apply the role:
+ansible-playbook ansible/playbooks/<role>.yml --limit <hostname> --check --diff
+ansible-playbook ansible/playbooks/<role>.yml --limit <hostname>
+```
+
+## Adding Ansible inventory entry
+
+```yaml
+# ansible/inventory/hosts.yml — under the appropriate group:
+new-host.sweet.home:
+  ansible_user: wayne
+  # any role-specific variables
+```
+
+## IPA enrollment (for any new host)
+
+```bash
+# On the new host (after OS install):
+sudo ipa-client-install \
+  --server=domain-controller.sweet.home \
+  --domain=sweet.home \
+  --realm=SWEET.HOME \
+  --principal=admin \
+  --mkhomedir
+```