add dark theme support

package.json

@@ -10,6 +10,7 @@
   },
   "dependencies": {
     "@radix-ui/react-dialog": "^1.1.15",
+    "@radix-ui/react-dropdown-menu": "^2.1.16",
     "@radix-ui/react-slot": "^1.2.3",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
@@ -18,6 +19,7 @@
     "lucide-react": "^0.539.0",
     "nanoid": "^5.1.5",
     "next": "15.4.6",
+    "next-themes": "^0.4.6",
     "react": "19.1.0",
     "react-dom": "19.1.0",
     "tailwind-merge": "^3.3.1"