Fix all NextAuth v4 imports across codebase

app/invitations/page.tsx

@@ -1,4 +1,5 @@
-import { auth } from '@/auth'
+import { getServerSession } from 'next-auth'
+import { authOptions } from '@/pages/api/auth/[...nextauth]'
 import { redirect } from 'next/navigation'
 import { getInvitations } from '@/lib/sharing-actions'
 import InvitationCard from '@/components/InvitationCard'
@@ -27,7 +28,7 @@ type Invitation = {
 }
 
 export default async function InvitationsPage() {
-  const session = await auth()
+  const session = await getServerSession(authOptions)
   
   if (!session?.user) {
     redirect('/auth/login')