feat: adopt material 3 theme and billing adjustments

lib/widgets/sms_scan/scan_progress_widget.dart

@@ -1,5 +1,5 @@
 import 'package:flutter/material.dart';
-import '../../theme/app_colors.dart';
+// Material colors only
 import '../../widgets/themed_text.dart';
 
 class ScanProgressWidget extends StatelessWidget {
@@ -20,7 +20,10 @@ class ScanProgressWidget extends StatelessWidget {
         // 진행 상태 표시
         LinearProgressIndicator(
           value: (currentIndex + 1) / totalCount,
-          backgroundColor: AppColors.navyGray.withValues(alpha: 0.2),
+          backgroundColor: Theme.of(context)
+              .colorScheme
+              .onSurfaceVariant
+              .withValues(alpha: 0.2),
           valueColor: AlwaysStoppedAnimation<Color>(
             Theme.of(context).colorScheme.primary,
           ),