feat: integrate react-router-dom for routing functionality

- Added react-router-dom to package.json and pnpm-lock.yaml.
- Created a new Layout component to manage sidebar and main content.
- Implemented AppRouter for defining application routes and redirection logic.

package.json

@@ -20,6 +20,7 @@
     "lucide-react": "^0.548.0",
     "react": "^19.1.1",
     "react-dom": "^19.1.1",
+    "react-router-dom": "^7.9.4",
     "tailwind-merge": "^3.3.1",
     "tailwindcss": "^4.1.16"
   },