Fix all NextAuth v4 imports across codebase

lib/migration-actions.ts

@@ -1,7 +1,8 @@
 'use server'
 
 import { prisma } from './db'
-import { auth } from '@/auth'
+import { getServerSession } from 'next-auth'
+import { authOptions } from '@/pages/api/auth/[...nextauth]'
 
 /**
  * Migration utilities for transitioning existing anonymous lists to user-owned lists
@@ -71,7 +72,7 @@ export async function getClaimableLists(listIds: string[]): Promise<ClaimableLis
 export async function claimLists(listIds: string[]): Promise<MigrationResult> {
   try {
     // Get current user session
-    const session = await auth()
+    const session = await getServerSession(authOptions)
     if (!session?.user?.id) {
       return { success: false, error: 'Unauthorized: Please log in to claim lists' }
     }
@@ -116,7 +117,7 @@ export async function claimLists(listIds: string[]): Promise<MigrationResult> {
  */
 export async function hasExistingLists(): Promise<boolean> {
   try {
-    const session = await auth()
+    const session = await getServerSession(authOptions)
     if (!session?.user?.id) {
       return false
     }