feat: added cookies to use subdomains

kittyurl-frontend/package.json

@@ -13,6 +13,7 @@
   "dependencies": {
     "@tailwindcss/vite": "^4.1.18",
     "axios": "^1.13.2",
+    "js-cookie": "^3.0.5",
     "js-sha512": "^0.9.0",
     "lucide-react": "^0.562.0",
     "react": "^19.2.0",
@@ -21,6 +22,7 @@
   },
   "devDependencies": {
     "@eslint/js": "^9.39.1",
+    "@types/js-cookie": "^3.0.6",
     "@types/node": "^24.10.1",
     "@types/react": "^19.2.5",
     "@types/react-dom": "^19.2.3",