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/ansible.cfg

@@ -0,0 +1,18 @@
+[defaults]
+inventory          = ./inventory/hosts.yml
+collections_path   = ./collections
+retry_files_enabled = False
+stdout_callback    = yaml
+host_key_checking  = True
+
+# Fail fast on unreachable hosts rather than silently skipping
+any_errors_fatal   = False
+
+# Use pipelining for speed (requires requiretty disabled in sudoers, which our roles handle)
+pipelining         = True
+
+[inventory]
+enable_plugins = yaml, ini
+
+[ssh_connection]
+ssh_args = -o ControlMaster=auto -o ControlPersist=60s -o ServerAliveInterval=30