fix: nextjs only reads .env files when using NEXT_PUBLIC_ in front of variables + definition of right .env of root

frontend/package-lock.json

@@ -10,6 +10,7 @@
       "dependencies": {
         "class-variance-authority": "^0.7.1",
         "clsx": "^2.1.1",
+        "dotenv": "^16.4.7",
         "libreoffice-convert": "^1.6.0",
         "lucide-react": "^0.475.0",
         "next": "15.1.6",
@@ -1983,6 +1984,18 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/dotenv": {
+      "version": "16.4.7",
+      "resolved": "https://registry.npmjs.org/dotenv/-/dotenv-16.4.7.tgz",
+      "integrity": "sha512-47qPchRCykZC03FhkYAhrvwU4xDBFIj1QPqaarj6mdM/hgUzfPHcpkHJOn3mJAufFeeAxAzeGsr5X0M4k6fLZQ==",
+      "license": "BSD-2-Clause",
+      "engines": {
+        "node": ">=12"
+      },
+      "funding": {
+        "url": "https://dotenvx.com"
+      }
+    },
     "node_modules/dunder-proto": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/dunder-proto/-/dunder-proto-1.0.1.tgz",