feat: replace native alerts with react-hot-toast notifications and update rider plan constants

src/app/layout.tsx

@@ -2,6 +2,7 @@ import type { Metadata } from "next";
 import { Inter } from "next/font/google";
 import "./globals.css";
 import Sidebar from "@/components/Sidebar";
+import { Toaster } from "react-hot-toast";
 
 const inter = Inter({
   variable: "--font-inter",
@@ -25,6 +26,7 @@ export default function RootLayout({
         <main className="lg:ml-64 min-h-screen">
           {children}
         </main>
+        <Toaster position="top-right" />
       </body>
     </html>
   );