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/external/index.md

@@ -0,0 +1,31 @@
+# Homelab
+
+A self-hosted infrastructure running on modest home hardware.
+
+## Self-hosted services
+
+| Service | What it does |
+|---------|-------------|
+| Nextcloud | Private cloud storage and sync |
+| Passbolt | Team password manager |
+| Gitea | Self-hosted Git with CI/CD |
+| SearXNG | Privacy-respecting meta-search engine |
+| Gramps Web | Family tree / genealogy |
+| Uptime Kuma | Service availability monitoring |
+
+## Infrastructure
+
+Built on:
+- **Proxmox VE** hypervisor running virtual machines and containers
+- **NixOS** for declarative, reproducible server configuration
+- **Docker** for containerised applications
+- **FreeIPA** for centralised identity and authentication
+- **Terraform** and **Ansible** for infrastructure as code
+- **Traefik** for reverse proxy with automatic TLS
+
+## Tech stack highlights
+
+- All infrastructure is declared in code — no manual configuration
+- Automated drift detection runs daily to catch any state inconsistencies
+- Secrets are encrypted at rest using SOPS + age
+- Automated documentation generated from live inventory