feat(l10n): 국제화(L10n) 시스템 도입 및 하드코딩 텍스트 변환

- flutter_localizations 및 intl 패키지 추가
- l10n.yaml 설정 파일 및 app_ko.arb 메시지 파일 생성
- 모든 화면(app, front, game_play, new_character, save_picker)의 하드코딩 텍스트를 L10n 키로 변환
- 테스트 파일에 localizationsDelegates 추가하여 L10n 지원

lib/src/features/front/front_screen.dart

@@ -1,5 +1,7 @@
 import 'package:flutter/material.dart';
 
+import 'package:askiineverdie/l10n/app_localizations.dart';
+
 class FrontScreen extends StatelessWidget {
   const FrontScreen({super.key, this.onNewCharacter, this.onLoadSave});
 
@@ -107,7 +109,7 @@ class _HeroHeader extends StatelessWidget {
                     crossAxisAlignment: CrossAxisAlignment.start,
                     children: [
                       Text(
-                        'Ascii Never Die',
+                        L10n.of(context).appTitle,
                         style: theme.textTheme.headlineSmall?.copyWith(
                           color: colorScheme.onPrimary,
                           fontWeight: FontWeight.w700,
@@ -126,14 +128,19 @@ class _HeroHeader extends StatelessWidget {
               ],
             ),
             const SizedBox(height: 14),
-            Wrap(
-              spacing: 8,
-              runSpacing: 8,
-              children: const [
-                _Tag(icon: Icons.cloud_off_outlined, label: 'No network'),
-                _Tag(icon: Icons.timer_outlined, label: 'Idle RPG loop'),
-                _Tag(icon: Icons.storage_rounded, label: 'Local saves'),
-              ],
+            Builder(
+              builder: (context) {
+                final l10n = L10n.of(context);
+                return Wrap(
+                  spacing: 8,
+                  runSpacing: 8,
+                  children: [
+                    _Tag(icon: Icons.cloud_off_outlined, label: l10n.tagNoNetwork),
+                    _Tag(icon: Icons.timer_outlined, label: l10n.tagIdleRpg),
+                    _Tag(icon: Icons.storage_rounded, label: l10n.tagLocalSaves),
+                  ],
+                );
+              },
             ),
           ],
         ),
@@ -151,6 +158,7 @@ class _ActionRow extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
+    final l10n = L10n.of(context);
 
     return Wrap(
       spacing: 12,
@@ -159,7 +167,7 @@ class _ActionRow extends StatelessWidget {
         FilledButton.icon(
           onPressed: onNewCharacter,
           icon: const Icon(Icons.casino_outlined),
-          label: const Text('New character'),
+          label: Text(l10n.newCharacter),
           style: FilledButton.styleFrom(
             padding: const EdgeInsets.symmetric(horizontal: 18, vertical: 14),
             textStyle: theme.textTheme.titleMedium,
@@ -168,7 +176,7 @@ class _ActionRow extends StatelessWidget {
         OutlinedButton.icon(
           onPressed: onLoadSave,
           icon: const Icon(Icons.folder_open),
-          label: const Text('Load save'),
+          label: Text(l10n.loadSave),
           style: OutlinedButton.styleFrom(
             padding: const EdgeInsets.symmetric(horizontal: 18, vertical: 14),
             textStyle: theme.textTheme.titleMedium,
@@ -177,7 +185,7 @@ class _ActionRow extends StatelessWidget {
         TextButton.icon(
           onPressed: () => _showPlaceholder(context),
           icon: const Icon(Icons.menu_book_outlined),
-          label: const Text('View build plan'),
+          label: Text(l10n.viewBuildPlan),
         ),
       ],
     );
@@ -189,11 +197,12 @@ class _StatusCards extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final l10n = L10n.of(context);
     return Column(
-      children: const [
+      children: [
         _InfoCard(
           icon: Icons.route_outlined,
-          title: 'Build roadmap',
+          title: l10n.buildRoadmap,
           points: [
             'Port PQ 6.4 data set (Config.dfm) into Dart constants.',
             'Recreate quest/task loop with deterministic RNG + saves.',
@@ -203,7 +212,7 @@ class _StatusCards extends StatelessWidget {
         SizedBox(height: 16),
         _InfoCard(
           icon: Icons.auto_fix_high_outlined,
-          title: 'Tech stack',
+          title: l10n.techStack,
           points: [
             'Flutter (Material 3) with multiplatform targets enabled.',
             'path_provider + shared_preferences for local storage hooks.',