♻️ refactor(App): use react router

this adds `MainPage`

src/components/pages/MainPage/MainPage.tsx

@@ -0,0 +1,31 @@
+import { useState } from 'react'
+import reactLogo from 'assets/react.svg'
+import viteLogo from '/vite.svg'
+import './MainPage.css'
+
+function MainPage() {
+  const [count, setCount] = useState(0)
+
+  return (
+    <>
+      <div>
+        <a href="https://vitejs.dev" target="_blank">
+          <img src={viteLogo} className="logo" alt="Vite logo" />
+        </a>
+        <a href="https://react.dev" target="_blank">
+          <img src={reactLogo} className="logo react" alt="React logo" />
+        </a>
+      </div>
+      <h1>Vite + React</h1>
+      <div className="card">
+        <button onClick={() => setCount(count => count + 1)}>count is {count}</button>
+        <p>
+          Edit <code>src/App.tsx</code> and save to test HMR
+        </p>
+      </div>
+      <p className="read-the-docs">Click on the Vite and React logos to learn more</p>
+    </>
+  )
+}
+
+export default MainPage