Add backup workflow

scripts/create-backup.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+repo_root="$(cd "$(dirname "$0")/.." && pwd)"
+output_dir="${1:-$repo_root/backups}"
+
+if ! git -C "$repo_root" rev-parse --is-inside-work-tree >/dev/null 2>&1; then
+  echo "Kein Git-Repository gefunden: $repo_root" >&2
+  exit 1
+fi
+
+mkdir -p "$output_dir"
+
+timestamp="$(date +%Y%m%d-%H%M%S)"
+short_sha="$(git -C "$repo_root" rev-parse --short HEAD)"
+archive_name="ruhepunkt-${timestamp}-${short_sha}.tar.gz"
+archive_path="$output_dir/$archive_name"
+
+git -C "$repo_root" archive \
+  --format=tar.gz \
+  --output="$archive_path" \
+  HEAD
+
+echo "Backup erstellt: $archive_path"