feat(auth): 添加启动认证功能

- 在本地化文件中添加认证相关的多语言支持
- 实现密码验证逻辑和锁定机制
- 创建登录页面UI组件
- 集成路由保护，未认证用户自动重定向到登录页
- 支持密码错误次数限制和倒计时锁定功能

lib/features/auth/providers/auth_provider.dart

@@ -0,0 +1,98 @@
+import 'dart:async';
+
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+
+import '../../settings/services/settings_service.dart';
+
+/// 认证状态枚举
+enum AuthStatus { unauthenticated, authenticated }
+
+/// 认证状态数据
+class AuthState {
+  final AuthStatus status;
+  final int remainingAttempts;
+  final DateTime? lockUntil;
+
+  const AuthState({
+    this.status = AuthStatus.unauthenticated,
+    this.remainingAttempts = 5,
+    this.lockUntil,
+  });
+
+  bool get isLocked => lockUntil != null && DateTime.now().isBefore(lockUntil!);
+
+  int get lockSecondsRemaining {
+    if (lockUntil == null) return 0;
+    final diff = lockUntil!.difference(DateTime.now()).inSeconds;
+    return diff > 0 ? diff : 0;
+  }
+
+  AuthState copyWith({
+    AuthStatus? status,
+    int? remainingAttempts,
+    DateTime? Function()? lockUntil,
+  }) {
+    return AuthState(
+      status: status ?? this.status,
+      remainingAttempts: remainingAttempts ?? this.remainingAttempts,
+      lockUntil: lockUntil != null ? lockUntil() : this.lockUntil,
+    );
+  }
+}
+
+/// 认证状态管理器
+class AuthNotifier extends StateNotifier<AuthState> {
+  AuthNotifier() : super(const AuthState());
+
+  static const maxAttempts = 5;
+  static const lockDuration = Duration(seconds: 30);
+
+  /// 验证密码
+  Future<bool> verify(String password) async {
+    if (state.isLocked) {
+      return false;
+    }
+
+    final isValid = await SettingsService.instance.verifyPassword(password);
+
+    if (isValid) {
+      state = const AuthState(status: AuthStatus.authenticated);
+      return true;
+    }
+
+    final newAttempts = state.remainingAttempts - 1;
+
+    if (newAttempts <= 0) {
+      state = state.copyWith(
+        remainingAttempts: 0,
+        lockUntil: () => DateTime.now().add(lockDuration),
+      );
+      _startLockTimer();
+    } else {
+      state = state.copyWith(remainingAttempts: newAttempts);
+    }
+
+    return false;
+  }
+
+  /// 锁定倒计时结束后自动解锁
+  void _startLockTimer() {
+    Timer(lockDuration, () {
+      if (state.status == AuthStatus.authenticated) return;
+      state = AuthState(
+        status: state.status,
+        remainingAttempts: maxAttempts,
+        lockUntil: null,
+      );
+    });
+  }
+
+  /// 重置认证状态（用于登出）
+  void reset() {
+    state = const AuthState();
+  }
+}
+
+final authProvider = StateNotifierProvider<AuthNotifier, AuthState>((ref) {
+  return AuthNotifier();
+});