fix: lottie CDN을 로컬 파일로 변경 (Tracking Prevention 차단 해결)

backend/templates/admin.html

@@ -665,7 +665,7 @@
         </div>
     </div>
 
-    <script src="https://cdnjs.cloudflare.com/ajax/libs/lottie-web/5.12.2/lottie.min.js"></script>
+    <script src="/static/js/lottie.min.js"></script>
     <script>
         function showTransactionDetail(transactionId) {
             document.getElementById('transactionModal').style.display = 'block';