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/playbooks/freeipa.yml

@@ -0,0 +1,18 @@
+---
+- name: FreeIPA server provisioning
+  hosts: freeipa
+  become: true
+  gather_facts: true
+
+  pre_tasks:
+    - name: Confirm Rocky Linux 9
+      ansible.builtin.assert:
+        that:
+          - ansible_distribution == "Rocky"
+          - ansible_distribution_major_version == "9"
+        fail_msg: "FreeIPA role targets Rocky Linux 9 only."
+      tags: always
+
+  roles:
+    - role: freeipa
+      tags: freeipa