Add real-time updates and fix delete button state

- Simplified useRealtimeSync to use router.refresh() polling
- Created RealtimeUpdater component for easy integration
- Added real-time updates to home page (3s polling)
- Fixed DeleteItemButton to properly reset state on error
- Updates now refresh every 3 seconds and on window focus
- Changes from other users/browsers will appear quickly

app/page.tsx

@@ -3,6 +3,7 @@ import ListCard from '@/components/ListCard'
 import NewListButton from '@/components/NewListButton'
 import GlobalSearch from '@/components/GlobalSearch'
 import EmptyState from '@/components/EmptyState'
+import RealtimeUpdater from '@/components/RealtimeUpdater'
 import Link from 'next/link'
 import { getServerSession } from 'next-auth'
 import { authOptions } from '@/pages/api/auth/[...nextauth]'
@@ -21,6 +22,7 @@ export default async function Home() {
 
   return (
     <main className="container mx-auto px-4 sm:px-6 py-6 sm:py-8 max-w-7xl">
+      <RealtimeUpdater pollInterval={3000} />
       <div className="flex flex-col sm:flex-row items-start sm:items-center justify-between gap-4 mb-6 sm:mb-8">
         <h1 className="text-2xl sm:text-3xl lg:text-4xl font-bold text-gray-900">Ultimate Lists</h1>
         <div className="flex items-center gap-3">