Add NotFoundPage component for handling 404 errors with user-friendly message

src/pages/notFound/index.tsx

@@ -0,0 +1,20 @@
+import { Box, Typography } from "@mui/material";
+import React from "react";
+
+const NotFoundPage: React.FC = () => {
+  return (
+    <Box
+      display="flex"
+      justifyContent="center"
+      alignItems="center"
+      height="100vh"
+      bgcolor="#f4f4f4"
+    >
+      <Typography variant="h4" color="textPrimary" fontWeight="bold">
+        404 - Page Not Found
+      </Typography>
+    </Box>
+  );
+};
+
+export default NotFoundPage;