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/inventory/group_vars/all.yml

@@ -0,0 +1,20 @@
+---
+# Variables applied to every host.
+# Override per-group in group_vars/<group>.yml or per-host in host_vars/<host>/vars.yml.
+
+ansible_python_interpreter: /usr/bin/python3
+
+# LAN domain
+lan_domain: sweet.home
+tailnet_domain: tail13f623.ts.net
+
+# DNS: FreeIPA is the authoritative resolver for sweet.home (Pi-hole decommissioned).
+# All LAN clients point directly to domain-controller.sweet.home for DNS.
+ipa_realm: SWEET.HOME
+ipa_server: domain-controller.sweet.home
+
+# Docker access GID — must match FreeIPA docker-access group GID
+docker_access_gid: 50010
+
+# IPA admins group granted passwordless sudo on all enrolled hosts
+ipa_admin_group: admins

ansible/inventory/group_vars/proxmox.yml

@@ -0,0 +1,14 @@
+---
+# Proxmox-group defaults.
+# Per-host overrides go in host_vars/pve1.sweet.home/vars.yml etc.
+
+# proxmox-hardening role toggles
+proxmox_harden_ssh: true
+proxmox_configure_firewall: true
+proxmox_configure_unattended_upgrades: true
+proxmox_switch_to_nosub_repo: true
+proxmox_disable_nag: true
+proxmox_setup_ipa_sudo: true
+
+# Firewall: management CIDR — override per host if subnets differ
+# proxmox_mgmt_cidr is set per host in hosts.yml

ansible/inventory/group_vars/raspi.yml

@@ -0,0 +1,5 @@
+---
+# Raspberry Pi group defaults.
+
+raspberrypi_setup_ipa_sudo: true
+raspberrypi_pin_docker_gid: true

ansible/inventory/hosts.yml

@@ -0,0 +1,79 @@
+---
+# Full infrastructure inventory.
+# IPs are documented here for reference; use FQDNs where DNS is reliable.
+# Hosts marked [nixos] are managed by the NixOS flake (nixos/) and are present
+# here only for Ansible tasks that apply to them (e.g. drift-check pings).
+
+all:
+  children:
+
+    # ── Proxmox hypervisors ───────────────────────────────────────────────────
+    proxmox:
+      hosts:
+        pve1.sweet.home:
+          ansible_user: wayne
+          proxmox_node_name: pve
+          proxmox_role: production
+          proxmox_mgmt_cidr: "192.168.2.0/24"
+          proxmox_admin_username: wayne
+        pve-test.sweet.home:
+          ansible_user: wayne
+          proxmox_node_name: pve-test
+          proxmox_role: sandbox
+          proxmox_mgmt_cidr: "192.168.2.0/24"
+          proxmox_admin_username: wayne
+
+    # ── Identity / DNS ────────────────────────────────────────────────────────
+    freeipa:
+      hosts:
+        domain-controller.sweet.home:
+          ansible_user: wayne
+          # IPA server parameters (consumed by freeipa role)
+          ipa_realm: "SWEET.HOME"
+          ipa_domain: "sweet.home"
+          ipa_hostname: "domain-controller.sweet.home"
+          ipa_ip: "192.168.2.253"
+          ipa_dns_forwarder: "192.168.2.138"  # Pi-hole
+          ansible_python_interpreter: /usr/bin/python3
+
+    # ── Edge / monitoring ─────────────────────────────────────────────────────
+    raspi:
+      hosts:
+        raspberrypi.tail13f623.ts.net:
+          ansible_user: wayne
+          docker_access_gid: 50010
+
+    # ── NixOS hosts (flake-managed; present for ping/audit tasks only) ────────
+    nixos:
+      vars:
+        ansible_note: >
+          These hosts are managed by the NixOS flake in nixos/.
+          Only non-NixOS tasks (connectivity checks, IPA enrollment helpers)
+          should target this group directly from Ansible.
+      hosts:
+        docker.sweet.home:
+          ansible_host: 192.168.2.225
+          ansible_user: wayne
+          nixos_build_type: docker
+        nix-cache.sweet.home:
+          ansible_host: 192.168.2.224
+          ansible_user: wayne
+          nixos_build_type: nix-cache
+
+    # ── Groupings for playbook targeting ─────────────────────────────────────
+    linux:
+      children:
+        proxmox: {}
+        freeipa: {}
+        raspi: {}
+        nixos: {}
+
+    network:
+      children:
+        freeipa: {}
+
+    non_nixos:
+      children:
+        proxmox: {}
+        freeipa: {}
+        raspi: {}