feat(client): Flutter 逐屏还原 + iPad ≥900 断点 (tsk_gpPXi-icyeOE)

对照 design/ui_kits mobile+tablet 原型逐屏补齐 Flutter 客户端:

- l10n 资源层(strings_zh/en,单显)+ Riverpod 状态层(连接状态机/免费额度/
  节点选择/语言/主题),UI 与数据解耦,mock 数据接 API 不动 UI。
- 连接键严格三态(off 虚线轨道环 / connecting 旋转弧 / on 满环+计时+光晕),
  状态来自 connectionProvider,点击只派发事件——禁止乐观显示。
- 节点页置顶「智能选择」推荐卡(clay 渐变 zap + 推荐胶囊,默认选中);
  免费额度卡(剩余分钟+进度条 ≤3 分钟切 warning + 看广告解锁变绿)。
- Tab 左右滑动切换(手势竞技场仲裁,子页滚动不误触发,200ms 方向感知滑入)。
- iPad/宽屏 ≥900 LayoutBuilder 切侧栏分栏(导航行高 ≥48,连接页双栏/节点双列网格),
  复用同一批原子组件,不 fork 页面。
- 语义 token 零硬编码;文案全部走 l10n;套餐数字对齐 §7;无支付表单/emoji 国旗。
- CI 红线词扫描扩展到 client/lib;新增 Flutter analyze+test CI 任务。
- 测试:连接状态机/额度/节点单测、连接键三态与卡片组件测试、
  golden(连接键三态/推荐卡/额度卡 × 明暗)。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/lib/l10n/strings_en.dart

@@ -0,0 +1,247 @@
+// strings_en.dart — English copy resources (single-language display)
+//
+// Red-line words forbidden: VPN / 翻墙 / 科学上网 / 突破封锁 / 自由穿越 / Go anywhere.
+// Positioning: network acceleration / experience optimization + privacy.
+// Plan numbers follow design/CLAUDE.md §7.
+import 'app_text.dart';
+
+class StringsEn extends AppText {
+  const StringsEn();
+
+  @override
+  AppLang get lang => AppLang.en;
+
+  @override
+  String get brand => 'Pangolin';
+  @override
+  String get online => '● Online';
+  @override
+  String get offline => '○ Offline';
+  @override
+  String get capOff => 'Tap to connect';
+  @override
+  String get capConnecting => 'Connecting…';
+  @override
+  String get capOn => 'Connected · Encrypted';
+  @override
+  String get connectNow => 'CONNECT';
+  @override
+  String get secure => 'SECURE';
+
+  @override
+  String get tabConnect => 'Connect';
+  @override
+  String get tabServers => 'Servers';
+  @override
+  String get tabStats => 'Stats';
+  @override
+  String get tabMe => 'Account';
+
+  @override
+  String get currentNode => 'Current node';
+  @override
+  String get download => 'Down';
+  @override
+  String get upload => 'Up';
+  @override
+  String get latency => 'Ping';
+
+  @override
+  String get quotaToday => 'Left today';
+  @override
+  String get minutes => 'min';
+  @override
+  String get quotaFree => 'Free · 10 min/day';
+  @override
+  String get watchAd => 'Watch ad to start';
+  @override
+  String get adUnlocked => 'Unlocked for today';
+
+  @override
+  String get chooseNode => 'Choose server';
+  @override
+  String get searchPh => 'Search country / city';
+  @override
+  String get smartSelect => 'Smart select';
+  @override
+  String get smartSub => 'Picks the best node for your network';
+  @override
+  String get recommended => 'Recommended';
+
+  @override
+  String get statsTitle => 'Statistics';
+  @override
+  String get trafficMonth => 'Traffic';
+  @override
+  String get avgPing => 'Avg ping';
+  @override
+  String get durMonth => 'Time';
+  @override
+  String get weekTraffic => 'This week (GB)';
+  @override
+  List<String> get days7 => const ['M', 'T', 'W', 'T', 'F', 'S', 'S'];
+
+  @override
+  String get meTitle => 'Account';
+  @override
+  String get proMember => 'PRO member';
+  @override
+  String get freePlanName => 'Free';
+  @override
+  String get expires => 'Expires';
+  @override
+  String get upgradeBtn => 'Renew / Upgrade';
+  @override
+  String get accInfoTitle => 'Account info';
+  @override
+  String get accEmail => 'Email';
+  @override
+  String get accPassword => 'Password';
+  @override
+  String get accChange => 'Change';
+  @override
+  String get myDevices => 'My devices';
+  @override
+  String get devicesSub => 'Up to 5 devices on PRO';
+  @override
+  String get thisDevice => 'This device';
+  @override
+  String get remove => 'Remove';
+  @override
+  String get redeemEntry => 'Redeem & buy';
+  @override
+  String get contactEntry => 'Contact us';
+  @override
+  String get signOut => 'Sign out';
+  @override
+  String get language => 'Language';
+  @override
+  String get darkAppearance => 'Dark appearance';
+  @override
+  String get stateOn => 'On';
+  @override
+  String get followLight => 'Off';
+  @override
+  String get protocol => 'Protocol';
+
+  @override
+  String get choosePlan => 'Choose plan';
+  @override
+  String get freePlan => 'Free';
+  @override
+  String get proPlan => 'Pro';
+  @override
+  String get teamPlan => 'Team';
+  @override
+  String get perMonth => '/mo';
+  @override
+  String get current => 'Current';
+  @override
+  String get upgrade => 'Upgrade';
+  @override
+  String get choose => 'Choose';
+  @override
+  String get mostPopular => 'Popular';
+  @override
+  List<String> get featsFree => const [
+        '1 basic node only',
+        '10 min per day',
+        'Watch an ad to start',
+        '7-day free trial on sign-up',
+      ];
+  @override
+  List<String> get featsPro =>
+      const ['80+ locations', 'Unlimited · fast', '5 devices', 'Streaming optimized'];
+  @override
+  List<String> get featsTeam =>
+      const ['Everything in Pro', '10 seats', 'Central billing', 'Priority support'];
+
+  @override
+  String get redeemTitle => 'Redeem & buy';
+  @override
+  String get redeemCodeTitle => 'Redeem a code';
+  @override
+  String get redeemPh => 'Enter activation code';
+  @override
+  String get redeemBtn => 'Redeem';
+  @override
+  String get redeemOk => 'Activated · PRO unlocked';
+  @override
+  String get buyTitle => 'Where to buy';
+  @override
+  String get buySub => 'In-app payment is unavailable. Get a code via:';
+  @override
+  String get chStore => 'Self-serve store';
+  @override
+  String get chEmail => 'Email support';
+
+  @override
+  String get contactTitle => 'Contact us';
+  @override
+  String get contactIntro =>
+      'Need help? Reach us via any channel below — usually replies in minutes.';
+  @override
+  String get contactEmail => 'Email support';
+  @override
+  String get contactStore => 'Self-serve store';
+  @override
+  String get contactHoursTitle => 'Support hours';
+  @override
+  String get contactHours => 'Daily 9:00 – 24:00 (GMT+8)';
+
+  @override
+  String get authTagline => 'Fast · Stable · Effortless';
+  @override
+  String get tabLogin => 'Log in';
+  @override
+  String get tabRegister => 'Sign up';
+  @override
+  String get emailLabel => 'Email';
+  @override
+  String get emailPh => 'your@email.com';
+  @override
+  String get pwLabel => 'Password';
+  @override
+  String get pwPh => 'Enter password';
+  @override
+  String get setPwPh => 'Set a password (for multi-device login)';
+  @override
+  String get codeLabel => 'Verification code';
+  @override
+  String codeSentTo(String email) => 'Code sent to $email';
+  @override
+  String get sendCode => 'Send code';
+  @override
+  String get resend => 'Resend';
+  @override
+  String get doLogin => 'Log in';
+  @override
+  String get doNext => 'Next';
+  @override
+  String get doCreate => 'Create account';
+  @override
+  String get forgotPw => 'Forgot password?';
+  @override
+  String get tos => 'By continuing you agree to our Terms & Privacy Policy';
+
+  @override
+  String get obSkip => 'Skip';
+  @override
+  String get obNext => 'Next';
+  @override
+  String get obAllow => 'Allow & continue';
+  @override
+  String get obStart => 'Get started';
+  @override
+  String get ob1Title => 'Connect worldwide';
+  @override
+  String get ob1Sub => '80+ locations, auto-fastest routing, rock-solid.';
+  @override
+  String get ob2Title => 'Allow network setup';
+  @override
+  String get ob2Sub => 'The system will ask to add a network profile to build the encrypted tunnel.';
+  @override
+  String get ob3Title => 'Private by design';
+  @override
+  String get ob3Sub => 'End-to-end encrypted. We keep zero browsing logs.';
+}