chore: remove unused next-themes dependency (#180)

Author: satnaing

package.json

@@ -45,7 +45,6 @@
     "input-otp": "^1.4.2",
     "js-cookie": "^3.0.5",
     "lucide-react": "^0.525.0",
-    "next-themes": "^0.4.6",
     "react": "^19.1.0",
     "react-day-picker": "9.8.0",
     "react-dom": "^19.1.0",