feat: implement loading state and error handling in PricingSection; add Suspense for async components in Pricing and Settings pages

app/settings/page.tsx

@@ -1,4 +1,6 @@
+import { Suspense } from 'react'
 import ProfileSettings from '@/components/settings/ProfileSettings'
+import CheckoutSuccessToast from '@/components/checkout/CheckoutSuccessToast'
 
 export const metadata = {
   title: 'Settings - Pulse',
@@ -8,6 +10,9 @@ export const metadata = {
 export default function SettingsPage() {
   return (
     <div className="min-h-screen pt-12 pb-12 px-4 sm:px-6">
+      <Suspense fallback={null}>
+        <CheckoutSuccessToast />
+      </Suspense>
       <ProfileSettings />
     </div>
   )