More converting to typescript

frontend/package.json

@@ -21,9 +21,10 @@
     "tailwind-merge": "^3.4.0"
   },
   "devDependencies": {
-    "@eslint/js": "^9.39.1",
+    "@eslint/js": "^9.39.4",
     "@testing-library/jest-dom": "^6.9.1",
     "@testing-library/react": "^16.3.2",
+    "@types/node": "^25.4.0",
     "@types/react": "^19.2.7",
     "@types/react-dom": "^19.2.3",
     "@vitejs/plugin-react": "^5.1.1",
@@ -35,7 +36,8 @@
     "jsdom": "^28.0.0",
     "postcss": "^8.5.6",
     "tailwindcss": "^4.1.18",
+    "typescript-eslint": "^8.57.0",
     "vite": "^7.3.1",
     "vitest": "^4.0.18"
   }
-}
+}