feat(client): 登录体验 — 记住邮箱 + 密码显隐 + 7天免登陆

1. 记住邮箱:登录页预填上次邮箱(TokenStore.saveLastEmail,登录/注册成功时存,
   退出登录不清除)。
2. 密码显隐:登录/注册密码框加眼睛按钮切换明文(PangolinIcons.eye/eyeOff)。
3. 7天免登陆:RootFlow 改为响应 authProvider——启动时有有效会话直接进主界面;
   AuthNotifier.refresh() 在服务端拒绝(refresh 过期/超 7 天)时 logout 回登录页,
   网络错误则保留会话。会话恢复期间显示极简启动屏。

flutter analyze 0 error;114 tests passed。

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

client/lib/main.dart

@@ -7,8 +7,10 @@ import 'pangolin_theme.dart';
 import 'services/token_store.dart';
 import 'shell/home_shell.dart';
 import 'state/app_providers.dart';
+import 'state/auth_provider.dart';
 import 'widgets/auth_screen.dart';
 import 'widgets/onboarding_screen.dart';
+import 'widgets/pangolin_logo.dart';
 
 void main() => runApp(const ProviderScope(child: PangolinApp()));
 
@@ -29,9 +31,8 @@ class PangolinApp extends ConsumerWidget {
   }
 }
 
-/// 应用阶段:登录 → 引导 → 主应用
-enum AppStage { auth, onboarding, app }
-
+/// 应用根流转:启动时若已有有效会话(7 天内 refresh 有效)直接进主界面,
+/// 免登陆;会话失效则回登录页。引导页仅首次注册/登录后看一次。
 class RootFlow extends ConsumerStatefulWidget {
   const RootFlow({super.key});
   @override
@@ -39,32 +40,43 @@ class RootFlow extends ConsumerStatefulWidget {
 }
 
 class _RootFlowState extends ConsumerState<RootFlow> {
-  AppStage stage = AppStage.auth;
   final _store = const TokenStore();
+  bool _forceOnboarding = false;
 
-  // 登录后:引导只首次看过一次;之后直接进主界面。
+  // 登录/注册成功后:未看过引导才进引导,否则直接主界面。
   Future<void> _afterAuth() async {
     final onboarded = await _store.isOnboarded();
     if (!mounted) return;
-    setState(() => stage = onboarded ? AppStage.app : AppStage.onboarding);
+    setState(() => _forceOnboarding = !onboarded);
   }
 
   Future<void> _afterOnboarding() async {
     await _store.markOnboarded();
     if (!mounted) return;
-    setState(() => stage = AppStage.app);
+    setState(() => _forceOnboarding = false);
   }
 
   @override
   Widget build(BuildContext context) {
     final t = ref.watch(appTextProvider);
-    switch (stage) {
-      case AppStage.auth:
-        return AuthScreen(t: t, onDone: () { _afterAuth(); });
-      case AppStage.onboarding:
-        return OnboardingScreen(t: t, onDone: () { _afterOnboarding(); });
-      case AppStage.app:
-        return const HomeShell();
+    final auth = ref.watch(authProvider);
+
+    if (auth.isLoading) return const _Splash();
+    if (!auth.isLoggedIn) {
+      return AuthScreen(t: t, onDone: () { _afterAuth(); });
     }
+    if (_forceOnboarding) {
+      return OnboardingScreen(t: t, onDone: () { _afterOnboarding(); });
+    }
+    return const HomeShell();
   }
 }
+
+/// 会话恢复期间的极简启动屏(避免登录页一闪而过)。
+class _Splash extends StatelessWidget {
+  const _Splash();
+  @override
+  Widget build(BuildContext context) => const Scaffold(
+        body: Center(child: PangolinMark(size: 56)),
+      );
+}

client/lib/services/token_store.dart

@@ -14,6 +14,7 @@ class TokenStore {
   static const _kAccess = 'pangolin_access_token';
   static const _kRefresh = 'pangolin_refresh_token';
   static const _kOnboarded = 'pangolin_onboarded';
+  static const _kLastEmail = 'pangolin_last_email';
 
   Future<void> saveTokens({
     required String access,
@@ -34,4 +35,8 @@ class TokenStore {
   // 首次引导标记:引导页只在第一次看(看完置位,后续登录直接进主界面)。
   Future<void> markOnboarded() => _storage.write(key: _kOnboarded, value: '1');
   Future<bool> isOnboarded() async => (await _storage.read(key: _kOnboarded)) == '1';
+
+  // 记住上次登录邮箱(登录页预填;退出登录不清除)。
+  Future<void> saveLastEmail(String email) => _storage.write(key: _kLastEmail, value: email);
+  Future<String?> loadLastEmail() => _storage.read(key: _kLastEmail);
 }

client/lib/state/auth_provider.dart

@@ -60,6 +60,11 @@ class AuthNotifier extends StateNotifier<AuthState> {
     try {
       await saveTokens(await _api.refresh(rt));
       return true;
+    } on AuthApiException catch (e) {
+      // 服务端明确拒绝(refresh 过期/失效,超出 7 天)→ 退出登录回登录页;
+      // 网络错误(statusCode<=0)则保留会话,稍后重试。
+      if (e.statusCode > 0) await logout();
+      return false;
     } catch (_) {
       return false;
     }

client/lib/widgets/auth_screen.dart

@@ -32,6 +32,7 @@ class _AuthScreenState extends ConsumerState<AuthScreen> {
   int _step = 0;
   bool _sent = false;
   bool _loading = false;
+  bool _pwVisible = false;
   String? _errorZh;
 
   final _email = TextEditingController();
@@ -42,6 +43,17 @@ class _AuthScreenState extends ConsumerState<AuthScreen> {
 
   bool get _emailValid => RegExp(r'\S+@\S+\.\S+').hasMatch(_email.text);
 
+  @override
+  void initState() {
+    super.initState();
+    // 预填上次登录邮箱。
+    ref.read(tokenStoreProvider).loadLastEmail().then((email) {
+      if (email != null && email.isNotEmpty && mounted) {
+        setState(() => _email.text = email);
+      }
+    });
+  }
+
   @override
   void dispose() {
     _email.dispose();
@@ -71,6 +83,7 @@ class _AuthScreenState extends ConsumerState<AuthScreen> {
         code: _code.text.trim(),
         password: _pw.text,
       );
+      await ref.read(tokenStoreProvider).saveLastEmail(_email.text.trim());
       await ref.read(authProvider.notifier).saveTokens(tokens);
       if (mounted) widget.onDone();
     } on AuthApiException catch (e) {
@@ -85,6 +98,7 @@ class _AuthScreenState extends ConsumerState<AuthScreen> {
         email: _email.text.trim(),
         password: _pw.text,
       );
+      await ref.read(tokenStoreProvider).saveLastEmail(_email.text.trim());
       await ref.read(authProvider.notifier).saveTokens(tokens);
       if (mounted) widget.onDone();
     } on AuthApiException catch (e) {
@@ -182,13 +196,31 @@ class _AuthScreenState extends ConsumerState<AuthScreen> {
   InputDecoration get _bare =>
       const InputDecoration(border: InputBorder.none, isCollapsed: true, contentPadding: EdgeInsets.symmetric(vertical: 12));
 
+  // 密码输入 + 显示/隐藏切换(眼睛按钮)。
+  Widget _pwInput(PangolinScheme c, String hint) => Row(children: [
+        Expanded(
+          child: TextField(
+            controller: _pw,
+            obscureText: !_pwVisible,
+            decoration: _bare.copyWith(hintText: hint),
+            onChanged: (_) => setState(() {}),
+          ),
+        ),
+        GestureDetector(
+          onTap: () => setState(() => _pwVisible = !_pwVisible),
+          child: Padding(
+            padding: const EdgeInsets.only(left: 6),
+            child: Icon(_pwVisible ? PangolinIcons.eyeOff : PangolinIcons.eye, size: 18, color: c.fg3),
+          ),
+        ),
+      ]);
+
   Widget _login(PangolinScheme c, AppText t) {
     return Column(children: [
       _field(c, icon: PangolinIcons.mail, label: t.emailLabel,
           child: TextField(controller: _email, decoration: _bare.copyWith(hintText: t.emailPh), onChanged: (_) => setState(() {}))),
       const SizedBox(height: 16),
-      _field(c, icon: PangolinIcons.lock, label: t.pwLabel,
-          child: TextField(controller: _pw, obscureText: true, decoration: _bare.copyWith(hintText: t.pwPh), onChanged: (_) => setState(() {}))),
+      _field(c, icon: PangolinIcons.lock, label: t.pwLabel, child: _pwInput(c, t.pwPh)),
       Align(
         alignment: Alignment.centerRight,
         child: Padding(
@@ -239,8 +271,7 @@ class _AuthScreenState extends ConsumerState<AuthScreen> {
     return Column(children: [
       Row(children: [Icon(PangolinIcons.checkCircle, size: 15, color: c.success), const SizedBox(width: 7), Text(_email.text, style: PangolinText.sm.copyWith(color: c.fg2))]),
       const SizedBox(height: 16),
-      _field(c, icon: PangolinIcons.lock, label: t.pwLabel,
-          child: TextField(controller: _pw, obscureText: true, decoration: _bare.copyWith(hintText: t.setPwPh), onChanged: (_) => setState(() {}))),
+      _field(c, icon: PangolinIcons.lock, label: t.pwLabel, child: _pwInput(c, t.setPwPh)),
       const SizedBox(height: 18),
       PangolinButton(
         label: _loading ? '...' : t.doCreate,

client/lib/widgets/pangolin_icons.dart

@@ -18,6 +18,8 @@ class PangolinIcons {
 
   // ── 导航 / 操作 ──
   static const settings     = LucideIcons.settings;
+  static const eye          = LucideIcons.eye;
+  static const eyeOff       = LucideIcons.eyeOff;
   static const user         = LucideIcons.user;
   static const search       = LucideIcons.search;
   static const check        = LucideIcons.check;

client/test/golden/desktop_pages_golden_test.dart

@@ -30,6 +30,10 @@ class _NullTokenStore implements TokenStore {
   Future<void> markOnboarded() async {}
   @override
   Future<bool> isOnboarded() async => true;
+  @override
+  Future<void> saveLastEmail(String email) async {}
+  @override
+  Future<String?> loadLastEmail() async => null;
 }
 
 Future<void> _shoot(WidgetTester tester, NavView view, String name) async {

client/test/unit/connection_controller_test.dart

@@ -29,6 +29,10 @@ class _NullTokenStore implements TokenStore {
   Future<void> markOnboarded() async {}
   @override
   Future<bool> isOnboarded() async => true;
+  @override
+  Future<void> saveLastEmail(String email) async {}
+  @override
+  Future<String?> loadLastEmail() async => null;
 }
 
 // ── 辅助 ──────────────────────────────────────────────────────────

client/test/unit/nodes_provider_test.dart

@@ -23,6 +23,10 @@ class _NullTokenStore implements TokenStore {
   Future<void> markOnboarded() async {}
   @override
   Future<bool> isOnboarded() async => true;
+  @override
+  Future<void> saveLastEmail(String email) async {}
+  @override
+  Future<String?> loadLastEmail() async => null;
 }
 
 // 直接喂固定节点列表(不触发真实探针/HTTP)。

client/test/unit/quota_controller_test.dart

@@ -20,6 +20,10 @@ class _NullTokenStore implements TokenStore {
   Future<void> markOnboarded() async {}
   @override
   Future<bool> isOnboarded() async => true;
+  @override
+  Future<void> saveLastEmail(String email) async {}
+  @override
+  Future<String?> loadLastEmail() async => null;
 }
 
 ProviderContainer _container() => ProviderContainer(