feat: complete n8n stack setup

Docker Compose stack (n8n, PostgreSQL 16, Redis 7, 1 worker) with:
- nginx local proxy on port 8088, YunoHost TLS termination config
- helper scripts: backup/restore/import/export/update
- .env.example, README with architecture, ops commands, to-do list

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/restore-n8n.sh

@@ -0,0 +1,50 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+ROOT="$(dirname "$SCRIPT_DIR")"
+COMPOSE="$ROOT/compose/docker-compose.yml"
+ENV="$ROOT/.env"
+
+if [ -z "${1:-}" ]; then
+  echo "Verwendung: $0 <backup-verzeichnis>"
+  echo "Verfügbare Backups:"
+  ls -lht "$ROOT/backups/"
+  exit 1
+fi
+
+BACKUP="$1"
+if [ ! -d "$BACKUP" ]; then
+  echo "Fehler: Verzeichnis '$BACKUP' nicht gefunden."
+  exit 1
+fi
+
+# shellcheck source=/dev/null
+source "$ENV"
+
+echo "[restore] Stelle wieder her aus: $BACKUP"
+echo "[restore] Stack wird gestoppt..."
+docker compose -f "$COMPOSE" down
+
+# n8n data
+echo "[restore] n8n Daten..."
+rm -rf "$ROOT/data/n8n"
+mkdir -p "$ROOT/data/n8n"
+tar -xzf "$BACKUP/n8n-data.tar.gz" -C "$ROOT/data"
+
+# Postgres
+echo "[restore] Datenbank wird gestartet..."
+docker compose -f "$COMPOSE" up -d postgres
+echo "[restore] Warte auf PostgreSQL..."
+sleep 10
+
+echo "[restore] Datenbank-Restore..."
+docker compose -f "$COMPOSE" exec -T postgres \
+  psql -U "$POSTGRES_USER" -d "$POSTGRES_DB" \
+  < "$BACKUP/postgres.sql"
+
+echo "[restore] Stack wird neu gestartet..."
+docker compose -f "$COMPOSE" up -d
+
+echo "[restore] Fertig. Stack-Status:"
+docker compose -f "$COMPOSE" ps