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/export-workflows.sh

@@ -0,0 +1,17 @@
+#!/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"
+
+TIMESTAMP=$(date +"%Y%m%d_%H%M%S")
+OUTPUT_DIR="$ROOT/imports/workflows/export_$TIMESTAMP"
+mkdir -p "$OUTPUT_DIR"
+
+echo "[export-workflows] Exportiere alle Workflows → $OUTPUT_DIR"
+docker compose -f "$COMPOSE" exec n8n \
+  n8n export:workflow --all --output="/imports/workflows/export_$TIMESTAMP/"
+
+echo "[export-workflows] Fertig."
+ls -lh "$OUTPUT_DIR"