feat: implement Sonner notifications, add Setting model, and reorganize user management into settings navigation.

package.json

@@ -17,10 +17,12 @@
     "bcryptjs": "^3.0.3",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
+    "cn": "^0.2.6",
     "date-fns": "^4.4.0",
     "jose": "^6.2.10",
     "lucide-react": "^1.34.0",
     "next": "16.3.3",
+    "next-themes": "^0.4.6",
     "prisma": "^5.22.0",
     "react": "19.2.8",
     "react-day-picker": "^10.0.1",
@@ -28,6 +30,7 @@
     "react-hook-form": "^7.86.0",
     "recharts": "^3.10.1",
     "shadcn": "^4.19.0",
+    "sonner": "^2.0.8",
     "tailwind-merge": "^3.6.0",
     "tw-animate-css": "^1.4.0",
     "uuid": "^14.0.2",