Refactor deployment scripts to improve Node.js version handling and PM2 process management

- Updated `ensure_node_version` function in `deploy-production.sh` and `deploy-test.sh` to use a common script for Node.js version validation.
- Simplified PM2 instance restart logic by introducing `deploy_restart_pm2` function in a new `deploy-runtime.sh` script.
- Replaced direct PM2 commands with the new function to handle instance restarts and HTTP readiness checks.
- Modified PM2 configuration files to set the script directly instead of using `node` as the interpreter, allowing for better compatibility with older Node.js versions.
- Added tests for the new deployment runtime functions in `deploy-runtime.spec.ts` to ensure correct behavior during deployment.
- Updated `package-lock.json` to include new dependencies and ensure compatibility with the latest changes.

harheimertc.config.cjs

@@ -49,8 +49,9 @@ module.exports = {
     {
       name: 'harheimertc',
       // Nuxt 4 production build: direkt den Node-Server starten (kein "preview mode")
-      script: 'node',
-      args: '.output/server/index.mjs',
+      script: '.output/server/index.mjs',
+      // Der PM2-Daemon kann noch unter einer älteren Node-Version laufen.
+      interpreter: process.env.DEPLOY_NODE_BINARY || process.execPath,
       cwd: '/var/www/harheimertc',
       instances: 1,
       autorestart: true,