fix: Update imports to use @heroui/react for Card and Button components

Author: H1B0B0

frontend/src/components/MaintenancePage.tsx

@@ -1,4 +1,4 @@
-import { Card } from "@heroui/card";
+import { Card } from "@heroui/react";
 
 export default function MaintenancePage() {
   return (

frontend/src/components/ThemeSwitcher.tsx

@@ -1,7 +1,7 @@
 "use client";
 import { useTheme } from "next-themes";
 import { useEffect, useState } from "react";
-import { Button } from "@heroui/button";
+import { Button } from "@heroui/react";
 import { SunIcon, MoonIcon } from "@heroicons/react/24/outline";
 
 export default function ThemeSwitcher() {