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/raspi.yml

@@ -0,0 +1,22 @@
+---
+- name: Raspberry Pi setup
+  hosts: raspi
+  become: true
+  gather_facts: true
+
+  pre_tasks:
+    - name: Confirm IPA enrollment
+      ansible.builtin.stat:
+        path: /etc/ipa/default.conf
+      register: ipa_conf
+      tags: always
+
+    - name: Warn if not IPA-enrolled
+      ansible.builtin.debug:
+        msg: "WARNING: /etc/ipa/default.conf not found. IPA-dependent tasks will be skipped."
+      when: not ipa_conf.stat.exists
+      tags: always
+
+  roles:
+    - role: raspberrypi
+      tags: raspi