feat: adopt material 3 theme and billing adjustments

lib/widgets/analysis/monthly_expense_chart_card.dart

@@ -1,11 +1,11 @@
 import 'package:flutter/material.dart';
+import '../../theme/color_scheme_ext.dart';
 import 'package:fl_chart/fl_chart.dart';
 import 'dart:math' as math;
 import 'package:provider/provider.dart';
 import '../../services/currency_util.dart';
 import '../../providers/locale_provider.dart';
-import '../../theme/app_colors.dart';
-import '../glassmorphism_card.dart';
+// Glass 제거: Material 3 Card 사용
 import '../themed_text.dart';
 import '../../l10n/app_localizations.dart';
 import '../../utils/reduce_motion.dart';
@@ -75,11 +75,13 @@ class MonthlyExpenseChartCard extends StatelessWidget {
   }
 
   // 월간 지출 차트 데이터
-  List<BarChartGroupData> _getMonthlyBarGroups(String locale) {
+  List<BarChartGroupData> _getMonthlyBarGroups(
+      BuildContext context, String locale) {
     final List<BarChartGroupData> barGroups = [];
     final calculatedMax = monthlyData.fold<double>(
         0, (max, data) => math.max(max, data['totalExpense'] as double));
     final maxAmount = _calculateChartMaxY(calculatedMax, locale);
+    final scheme = Theme.of(context).colorScheme;
 
     for (int i = 0; i < monthlyData.length; i++) {
       final data = monthlyData[i];
@@ -89,20 +91,13 @@ class MonthlyExpenseChartCard extends StatelessWidget {
           barRods: [
             BarChartRodData(
               toY: data['totalExpense'],
-              gradient: LinearGradient(
-                colors: [
-                  const Color(0xFF3B82F6).withValues(alpha: 0.7),
-                  const Color(0xFF60A5FA),
-                ],
-                begin: Alignment.bottomCenter,
-                end: Alignment.topCenter,
-              ),
+              color: scheme.primary,
               width: 18,
               borderRadius: BorderRadius.circular(4),
               backDrawRodData: BackgroundBarChartRodData(
                 show: true,
                 toY: maxAmount,
-                color: AppColors.navyGray.withValues(alpha: 0.1),
+                color: scheme.onSurfaceVariant.withValues(alpha: 0.08),
               ),
             ),
           ],
@@ -132,10 +127,17 @@ class MonthlyExpenseChartCard extends StatelessWidget {
               parent: animationController,
               curve: const Interval(0.4, 0.9, curve: Curves.easeOut),
             )),
-            child: GlassmorphismCard(
-              blur: 10,
-              opacity: 0.1,
-              borderRadius: 16,
+            child: Card(
+              elevation: 3,
+              shape: RoundedRectangleBorder(
+                borderRadius: BorderRadius.circular(16),
+                side: BorderSide(
+                  color: Theme.of(context)
+                      .colorScheme
+                      .outline
+                      .withValues(alpha: 0.5),
+                ),
+              ),
               child: Padding(
                 padding: const EdgeInsets.all(16),
                 child: Column(
@@ -168,7 +170,7 @@ class MonthlyExpenseChartCard extends StatelessWidget {
                                     (max, data) => math.max(
                                         max, data['totalExpense'] as double)),
                                 locale),
-                            barGroups: _getMonthlyBarGroups(locale),
+                            barGroups: _getMonthlyBarGroups(context, locale),
                             gridData: FlGridData(
                               show: true,
                               drawVerticalLine: false,
@@ -182,8 +184,10 @@ class MonthlyExpenseChartCard extends StatelessWidget {
                                   CurrencyUtil.getDefaultCurrency(locale)),
                               getDrawingHorizontalLine: (value) {
                                 return FlLine(
-                                  color:
-                                      AppColors.navyGray.withValues(alpha: 0.1),
+                                  color: Theme.of(context)
+                                      .colorScheme
+                                      .onSurfaceVariant
+                                      .withValues(alpha: 0.1),
                                   strokeWidth: 1,
                                 );
                               },
@@ -222,14 +226,18 @@ class MonthlyExpenseChartCard extends StatelessWidget {
                             barTouchData: BarTouchData(
                               enabled: true,
                               touchTooltipData: BarTouchTooltipData(
-                                tooltipBgColor: AppColors.darkNavy,
+                                tooltipBgColor: Theme.of(context)
+                                    .colorScheme
+                                    .inverseSurface,
                                 tooltipRoundedRadius: 8,
                                 getTooltipItem:
                                     (group, groupIndex, rod, rodIndex) {
                                   return BarTooltipItem(
                                     '${monthlyData[group.x]['monthName']}\n',
-                                    const TextStyle(
-                                      color: AppColors.pureWhite,
+                                    TextStyle(
+                                      color: Theme.of(context)
+                                          .colorScheme
+                                          .onInverseSurface,
                                       fontWeight: FontWeight.bold,
                                     ),
                                     children: [
@@ -239,8 +247,10 @@ class MonthlyExpenseChartCard extends StatelessWidget {
                                                 monthlyData[group.x]
                                                     ['totalExpense'] as double,
                                                 locale),
-                                        style: const TextStyle(
-                                          color: Color(0xFFFBBF24),
+                                        style: TextStyle(
+                                          color: Theme.of(context)
+                                              .colorScheme
+                                              .warning,
                                           fontSize: 14,
                                           fontWeight: FontWeight.w500,
                                         ),