fix: 날짜 표시 UTC → KST 변환 (admin 페이지들)

backend/templates/admin_members.html

@@ -924,7 +924,8 @@
         const txs = detailData.mileage.transactions;
         container.innerHTML = txs.map(tx => {
             const isPositive = tx.points > 0;
-            const date = tx.created_at ? new Date(tx.created_at).toLocaleString('ko-KR', {
+            // DB는 UTC로 저장 → 'Z' 붙여서 UTC로 해석 → KST로 표시
+            const date = tx.created_at ? new Date(tx.created_at + 'Z').toLocaleString('ko-KR', {
                 month: 'short', day: 'numeric', hour: '2-digit', minute: '2-digit'
             }) : '';
             
@@ -1075,8 +1076,8 @@
         }
 
         container.innerHTML = detailData.interests.map(item => {
-            // 날짜 포맷
-            const date = item.created_at ? new Date(item.created_at).toLocaleString('ko-KR', {
+            // 날짜 포맷 (DB는 UTC → KST 변환)
+            const date = item.created_at ? new Date(item.created_at + 'Z').toLocaleString('ko-KR', {
                 month: 'short', day: 'numeric'
             }) : '';