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

.gitignore

@@ -0,0 +1,42 @@
+# Terraform state and credentials — never commit
+**/.terraform/
+**/*.tfstate
+**/*.tfstate.*
+**/terraform.tfvars
+**/.terraform.lock.hcl
+# keep .terraform.lock.hcl for reproducibility if you want — uncomment to track it:
+# !**/.terraform.lock.hcl
+
+# Ansible secrets and generated files
+ansible/inventory/host_vars/*/vault.yml
+ansible/.vault_pass
+**/*.retry
+
+# Docker secrets
+stacks/docker/secrets/stack-secrets.env
+stacks/docker/secrets/*.txt
+stacks/raspi/default-environment.env.local
+
+# SOPS / age private keys
+*.age
+.sops.yaml.local
+
+# Editor and OS
+.DS_Store
+*.swp
+*.swo
+*~
+.idea/
+.vscode/settings.json
+
+# MkDocs build output
+site/
+
+# Python
+__pycache__/
+*.pyc
+.venv/
+venv/
+
+# Logs
+*.log