feat: prepare nobat724_front for deployment on Liara platform

- Added Node.js engine requirement in package.json to ensure compatibility.
- Created liara-deploy.md for deployment instructions and environment setup.
- Added example environment variables in .env.liara.example for clarity.
- Introduced .liaraignore to exclude unnecessary files from deployment.
- Created liara.json for Liara configuration, including health check settings.
- Removed redundant next.config.mjs file to prevent configuration conflicts.

liara.json

@@ -0,0 +1,18 @@
+{
+  "port": 3000,
+  "platform": "next",
+  "app": "nobat724",
+  "build": {
+    "location": "germany"
+  },
+  "healthCheck": {
+    "command": "node -e \"require('http').get('http://127.0.0.1:3000/',r=>process.exit(r.statusCode?0:1)).on('error',()=>process.exit(1))\"",
+    "interval": 30,
+    "timeout": 10,
+    "retries": 3,
+    "startPeriod": 40
+  },
+  "next": {
+    "nodeVersion": "22"
+  }
+}