feat(i18n): 完成全量 UI 文本国际化，替换所有硬编码中文为 AppLocalizations 调用

- core/localization: 新增约 60 个翻译键（含参数化方法），中英双语覆盖
- shared/widgets: CommonDialog 默认参数国际化
- features/home: 完成页操作步骤指引、状态栏串口连接状态、程序列表状态标签
- features/programs: 表头状态列、表单验证提示、导入/模板操作反馈、删除确认（参数化）
- features/program_detail: 步骤列表/表单标题、删除确认、速度档位显示（参数化）
- features/device: run_state_provider 错误消息改为错误码
- features/settings: 升级页、密码面板、语言面板、U盘导入面板、串口配置面板全部替换

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

lib/features/settings/pages/settings_page.dart

@@ -116,11 +116,12 @@ class _SettingsPageState extends ConsumerState<SettingsPage> {
   }
 
   Widget _buildUpgradeContent() {
+    final l10n = AppLocalizations.of(context);
     return ListView(
       padding: EdgeInsets.zero,
       children: [
         Text(
-          '软件升级',
+          l10n?.upgrade ?? '软件升级',
           style: TextStyle(
             color: AppTheme.textPrimary,
             fontSize: 18,
@@ -139,7 +140,7 @@ class _SettingsPageState extends ConsumerState<SettingsPage> {
               Icon(Icons.info_outline, color: AppTheme.primaryColor),
               const SizedBox(width: 12),
               Text(
-                '当前版本: $_currentVersion',
+                '${l10n?.currentVersion ?? '当前版本'}: $_currentVersion',
                 style: TextStyle(color: AppTheme.textPrimary),
               ),
             ],
@@ -147,13 +148,13 @@ class _SettingsPageState extends ConsumerState<SettingsPage> {
         ),
         const SizedBox(height: 24),
         CommonButton(
-          text: '检查更新',
+          text: l10n?.checkUpdate ?? '检查更新',
           icon: Icons.refresh,
           type: ButtonType.primary,
           onPressed: () {
             ScaffoldMessenger.of(context).showSnackBar(
               SnackBar(
-                content: Text('已是最新版本'),
+                content: Text(l10n?.latestVersion ?? '已是最新版本'),
                 backgroundColor: AppTheme.successColor,
               ),
             );