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

scripts/install-hooks.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+# Install git pre-commit hook that runs gitleaks before every commit.
+# Idempotent — safe to re-run.
+set -euo pipefail
+
+REPO_ROOT="$(git rev-parse --show-toplevel)"
+HOOK="${REPO_ROOT}/.git/hooks/pre-commit"
+
+cat > "$HOOK" <<'EOF'
+#!/usr/bin/env bash
+set -e
+if ! command -v gitleaks &>/dev/null; then
+    echo "gitleaks not found — skipping pre-commit secret scan"
+    echo "Install: https://github.com/gitleaks/gitleaks#installing"
+    exit 0
+fi
+exec gitleaks protect --staged --config .gitleaks.toml --no-banner
+EOF
+
+chmod +x "$HOOK"
+echo "Pre-commit hook installed at ${HOOK}"