Ops: add Proxmox migration tooling and runbook

Add end-to-end migration scripts for inventory, precopy, cutover, smoke tests, rollback, and post-migration checks. Include an operational runbook and Proxmox env template to move Hördle behind Nginx Proxy Manager while preserving persistent volumes safely.

scripts/migration-postcheck.sh

@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Kontrollskript fuer die ersten 24h nach Migration.
+
+APP_DIR="${APP_DIR:-$(pwd)}"
+DOMAIN_URL="${DOMAIN_URL:-https://hoerdle.de}"
+CONTAINER_NAME="${CONTAINER_NAME:-hoerdle}"
+
+cd "$APP_DIR"
+
+echo "== Hördle Post-Migration Check =="
+echo "App dir: $APP_DIR"
+echo "Domain:  $DOMAIN_URL"
+echo
+
+echo "-- Container Status --"
+docker compose ps
+echo
+
+echo "-- Health Endpoint --"
+curl -fsS "$DOMAIN_URL/api/daily" >/dev/null
+echo "OK: /api/daily erreichbar"
+echo
+
+echo "-- Fehlerlogs (24h) --"
+docker compose logs --since=24h "$CONTAINER_NAME" 2>&1 | grep -Ei "(error|exception|fatal|panic)" || true
+echo
+
+echo "-- Backup Testlauf --"
+./scripts/backup-persistence.sh
+echo
+
+echo "Postcheck abgeschlossen."