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.

src/main.tsx

@@ -1,9 +1,10 @@
 import { StrictMode } from 'react'
 import { createRoot } from 'react-dom/client'
 import './index.css'
+import { AppRouter } from './router'
 
 createRoot(document.getElementById('root')!).render(
   <StrictMode>
-    {null}
+    <AppRouter />
   </StrictMode>
 )