Fix timezone issue in admin page formatDate function

pages/admin.vue

@@ -499,7 +499,8 @@ async function handleDelete() {
 }
 
 function formatDate(dateString: string) {
-  const date = new Date(dateString)
+  // Add T00:00:00 to ensure the date is interpreted as local time, not UTC
+  const date = new Date(dateString + 'T00:00:00')
   return date.toLocaleDateString('en-US', { 
     year: 'numeric', 
     month: 'long',