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/mkdocs.yml

@@ -0,0 +1,30 @@
+site_name: "Infrastructure — Internal Docs"
+site_description: "Internal documentation for the sweet.home homelab infrastructure"
+docs_dir: internal
+
+nav:
+  - Home: index.md
+  - Architecture: architecture.md
+  - Network Topology: network-topology.md
+  - Runbooks:
+    - Proxmox Hardening: runbooks/proxmox-hardening.md
+    - FreeIPA Setup: runbooks/freeipa-setup.md
+    - New Host Provisioning: runbooks/new-host.md
+    - Drift Detection: runbooks/drift-detection.md
+  - Generated:
+    - Host Inventory: generated/host-inventory.md
+    - Service Catalog: generated/service-catalog.md
+
+theme:
+  name: material
+  palette:
+    scheme: slate
+    primary: indigo
+
+validation:
+  nav:
+    omitted_files: ignore
+
+exclude_docs: |
+  README.md
+  *.example