fix: adjust subscription card layout

lib/widgets/subscription_card.dart

@@ -710,11 +710,17 @@ class _SubscriptionCardState extends State<SubscriptionCard>
     final icon = PaymentCardUtils.iconForName(card.iconName);
 
     return Chip(
-      avatar: CircleAvatar(
-        backgroundColor: Colors.white,
+      avatar: Container(
+        width: 20,
+        height: 20,
+        decoration: BoxDecoration(
+          color: color.withValues(alpha: 0.15),
+          shape: BoxShape.circle,
+        ),
+        alignment: Alignment.center,
         child: Icon(
           icon,
-          size: 14,
+          size: 12,
           color: color,
         ),
       ),

lib/widgets/subscription_list_widget.dart

@@ -58,7 +58,6 @@ class SubscriptionListWidget extends StatelessWidget {
                     shrinkWrap: true,
                     padding: const EdgeInsets.symmetric(horizontal: 16),
                     cacheExtent: 500,
-                    prototypeItem: const SizedBox(height: 156),
                     itemCount: subscriptions.length,
                     itemBuilder: (context, subIndex) {
                       // 각 구독의 지연값 계산 (순차적으로 나타나도록)