feat(www): make careers page background yellow

Add yellow background color to the careers page by wrapping the page
content in a div with bg-yellow-300 Tailwind class.

Slack thread: https://supabase.slack.com/archives/C0429V78ACX/p1770736416517109?thread_ts=1770735453.085769&cid=C0429V78ACX

https://claude.ai/code/session_01VHpskfvY89dYBmgF4ghUsp

apps/www/pages/careers.tsx

@@ -112,6 +112,7 @@ const CareerPage = ({ jobs, placeholderJob, contributors }: CareersPageProps) =>
         }}
       />
       <DefaultLayout>
+        <div className="bg-yellow-300">
         <header className="container relative mx-auto px-6 pt-12 pb-8 lg:pt-24 lg:px-16 xl:px-20 text-center space-y-4">
           <h1 className="text-sm text-brand md:text-base">
             <span className="sr-only">Supabase </span>Careers
@@ -442,6 +443,7 @@ const CareerPage = ({ jobs, placeholderJob, contributors }: CareersPageProps) =>
             </div>
           </SectionContainer>
         </div>
+        </div>
       </DefaultLayout>
     </>
   )