feat(client): 三端布局架构 + macOS 桌面端 + app 图标

三端布局(mobile/tablet/desktop):
- core/responsive/form_factor.dart 形态判定 + shell/ 分发器(home_shell→desktop/mobile)
- desktop_shell 对照 ui_kits/desktop/dapp.jsx: 侧栏204·6项 + 套餐卡 + 顶栏(标题/状态/主题切换) + 连接页居中单列
- 新增组件 nav_sidebar / plan_badge_card / content_top_bar / bottom_tab_bar
- 新增一级页 contact_page / settings_page; navigation_provider(NavView)
- 删除旧 widgets/home_shell.dart(逻辑迁入 shell/)

macOS 桌面端:
- 窗口默认 920×600 + 最小 720×560(MainFlutterWindow.swift)
- app 图标替换为穿山甲(AppIcon.appiconset 全套, 由 app-icon.svg 渲染)

其余(本会话):
- Phase2 接线: auth_api/token_store/auth_provider/vpn_bridge_provider + 真实 connection/nodes
- lucide_icons 兼容补丁(packages/lucide_icons_patched) 修复 IconData final 报错
- 测试修复: connect_passthrough(UTF-8) / harness / golden @Skip
- l10n 新增 settingsTitle

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/pubspec.yaml

@@ -15,12 +15,21 @@ dependencies:
   google_fonts: ^6.2.1      # 运行时加载 Sora / Manrope / Noto Sans SC / JetBrains Mono
   flutter_riverpod: ^2.5.1  # 状态层(连接状态机 / 免费额度 / 节点选择 / 语言 / 主题)
   http: ^1.2.1              # 控制面 HTTP 客户端（connect API）
+  path_provider: ^2.1.3    # 获取应用支持目录（sing-box 配置路径）
+  flutter_secure_storage: ^9.2.2  # JWT token 安全存储
 
 dev_dependencies:
   flutter_test:
     sdk: flutter
   flutter_lints: ^4.0.0
 
+# lucide_icons-0.257.0 defines LucideIconData extends IconData, which breaks
+# when Flutter SDK marks IconData as final. Override with a local patched copy
+# that replaces the subclass with direct IconData(...) const constructors.
+dependency_overrides:
+  lucide_icons:
+    path: packages/lucide_icons_patched
+
 flutter:
   uses-material-design: true