feat: 다국어 지원 및 다중 통화 환율 변환 기능 확대

- ExchangeRateService에 JPY, CNY 환율 지원 추가
- 구독 서비스별 다국어 표시 이름 지원
- 분석 화면 차트 및 UI/UX 개선
- 설정 화면 전면 리팩토링
- SMS 스캔 기능 사용성 개선
- 전체 앱 다국어 번역 확대

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

lib/widgets/detail/detail_form_section.dart

@@ -9,6 +9,7 @@ import '../common/form_fields/date_picker_field.dart';
 import '../common/form_fields/currency_selector.dart';
 import '../common/form_fields/billing_cycle_selector.dart';
 import '../common/form_fields/category_selector.dart';
+import '../../l10n/app_localizations.dart';
 
 /// 상세 화면 폼 섹션
 /// 구독 정보를 편집할 수 있는 폼 필드들을 포함합니다.
@@ -66,8 +67,8 @@ class DetailFormSection extends StatelessWidget {
                 BaseTextField(
                   controller: controller.serviceNameController,
                   focusNode: controller.serviceNameFocus,
-                  label: '서비스명',
-                  hintText: '예: Netflix, Spotify',
+                  label: AppLocalizations.of(context).subscriptionName,
+                  hintText: AppLocalizations.of(context).serviceNameExample,
                   textInputAction: TextInputAction.next,
                   onEditingComplete: () {
                     controller.monthlyCostFocus.requestFocus();
@@ -84,7 +85,7 @@ class DetailFormSection extends StatelessWidget {
                       child: CurrencyInputField(
                         controller: controller.monthlyCostController,
                         currency: controller.currency,
-                        label: '월 지출',
+                        label: AppLocalizations.of(context).monthlyExpense,
                         focusNode: controller.monthlyCostFocus,
                         textInputAction: TextInputAction.next,
                         onEditingComplete: () {
@@ -97,9 +98,9 @@ class DetailFormSection extends StatelessWidget {
                       child: Column(
                         crossAxisAlignment: CrossAxisAlignment.start,
                         children: [
-                          const Text(
-                            '통화',
-                            style: TextStyle(
+                          Text(
+                            AppLocalizations.of(context).currency,
+                            style: const TextStyle(
                               fontSize: 16,
                               fontWeight: FontWeight.w600,
                               color: AppColors.darkNavy,
@@ -134,9 +135,9 @@ class DetailFormSection extends StatelessWidget {
                 Column(
                   crossAxisAlignment: CrossAxisAlignment.start,
                   children: [
-                    const Text(
-                      '결제 주기',
-                      style: TextStyle(
+                    Text(
+                      AppLocalizations.of(context).billingCycle,
+                      style: const TextStyle(
                         fontSize: 16,
                         fontWeight: FontWeight.w600,
                         color: AppColors.darkNavy,
@@ -161,7 +162,7 @@ class DetailFormSection extends StatelessWidget {
                   onDateSelected: (date) {
                     controller.nextBillingDate = date;
                   },
-                  label: '다음 결제일',
+                  label: AppLocalizations.of(context).nextBillingDate,
                   firstDate: DateTime.now(),
                   lastDate: DateTime.now().add(const Duration(days: 365 * 2)),
                   primaryColor: baseColor,
@@ -174,9 +175,9 @@ class DetailFormSection extends StatelessWidget {
                     return Column(
                       crossAxisAlignment: CrossAxisAlignment.start,
                       children: [
-                        const Text(
-                          '카테고리',
-                          style: TextStyle(
+                        Text(
+                          AppLocalizations.of(context).category,
+                          style: const TextStyle(
                             fontSize: 16,
                             fontWeight: FontWeight.w600,
                             color: AppColors.darkNavy,