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-inventory.sh

@@ -0,0 +1,70 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Inventarisiert Persistenz und laufzeitrelevante Variablen für die Migration.
+# Das Skript verändert keine Daten.
+
+ROOT_DIR="${1:-$(pwd)}"
+cd "$ROOT_DIR"
+
+count_files_recursive() {
+  local dir="$1"
+  find "$dir" -type f 2>/dev/null | wc -l
+}
+
+echo "== Hördle Migrations-Inventur =="
+echo "Projektpfad: $(pwd)"
+echo
+
+required_paths=(
+  "data"
+  "data/prod.db"
+  "public/uploads"
+  "docker-compose.yml"
+  ".env"
+)
+
+echo "-- Existenzcheck --"
+for path in "${required_paths[@]}"; do
+  if [ -e "$path" ]; then
+    echo "[OK] $path"
+  else
+    echo "[FEHLT] $path"
+  fi
+done
+echo
+
+echo "-- Groesse und Dateizaehlung --"
+if [ -d "data" ]; then
+  du -sh "data"
+  DATA_FILE_COUNT="$(count_files_recursive "data")"
+  echo "Dateien in data/: $DATA_FILE_COUNT"
+fi
+
+if [ -d "public/uploads" ]; then
+  du -sh "public/uploads"
+  UPLOAD_FILE_COUNT="$(count_files_recursive "public/uploads")"
+  echo "Dateien in public/uploads/: $UPLOAD_FILE_COUNT"
+fi
+echo
+
+echo "-- DB Hash (Integritaetsreferenz) --"
+if [ -f "data/prod.db" ]; then
+  sha256sum "data/prod.db"
+else
+  echo "data/prod.db nicht gefunden."
+fi
+echo
+
+echo "-- Compose Persistenz-Mounts --"
+grep -E "^[[:space:]]*-[[:space:]]+\./(data|public/uploads):" "docker-compose.yml" || true
+echo
+
+echo "-- Runtime Variablen in Compose --"
+grep -E "^[[:space:]]*-[[:space:]]+(DATABASE_URL|ADMIN_PASSWORD|TZ|GOTIFY_URL|GOTIFY_APP_TOKEN|OPENROUTER_API_KEY)=" "docker-compose.yml" || true
+echo
+
+echo "-- Hinweise --"
+echo "1) Stelle sicher, dass .env nicht aus Versehen in Transfers/Backups an Dritte gelangt."
+echo "2) Fuer den Cutover muss die Quell-App vor Final-Sync gestoppt werden."
+echo "3) Nutze danach scripts/migration-precopy.sh und scripts/migration-cutover.sh."