feat: 新增隐私模式、全面的交易管理、预算与储蓄罐功能，并优化了整体用户界面和页面结构。

src/hooks/useNotifications.tsx

@@ -0,0 +1,142 @@
+
+import { useState, useEffect, useCallback, createContext, useContext } from 'react';
+
+export type NotificationType = 'info' | 'success' | 'warning' | 'error' | 'system';
+
+export interface Notification {
+    id: string;
+    type: NotificationType;
+    title: string;
+    message: string;
+    timestamp: number;
+    read: boolean;
+    link?: string;
+}
+
+interface NotificationContextType {
+    notifications: Notification[];
+    unreadCount: number;
+    markAsRead: (id: string) => void;
+    markAllAsRead: () => void;
+    deleteNotification: (id: string) => void;
+    addNotification: (notification: Omit<Notification, 'id' | 'timestamp' | 'read'>) => void;
+}
+
+const NotificationContext = createContext<NotificationContextType | undefined>(undefined);
+
+const STORAGE_KEY = 'novault_notifications';
+
+const MOCK_NOTIFICATIONS: Notification[] = [
+    {
+        id: '1',
+        type: 'system',
+        title: '系统升级通知',
+        message: 'Novault 已成功升级至 v2.3.0 版本，新增了专注模式和高级报表功能。',
+        timestamp: Date.now() - 1000 * 60 * 30, // 30 mins ago
+        read: false,
+        link: '/settings'
+    },
+    {
+        id: '2',
+        type: 'warning',
+        title: '预算预警',
+        message: '您的 "餐饮" 类别预算已使用 85%，请注意控制支出。',
+        timestamp: Date.now() - 1000 * 60 * 60 * 2, // 2 hours ago
+        read: false,
+        link: '/budget'
+    },
+    {
+        id: '3',
+        type: 'success',
+        title: '数据同步完成',
+        message: '您的本地数据已成功备份至云端。',
+        timestamp: Date.now() - 1000 * 60 * 60 * 24, // 1 day ago
+        read: true,
+    },
+    {
+        id: '4',
+        type: 'info',
+        title: '新功能推荐',
+        message: '试试新的 "专注模式"，点击右上角头像即可切换。',
+        timestamp: Date.now() - 1000 * 60 * 60 * 48, // 2 days ago
+        read: true,
+    },
+    {
+        id: '5',
+        type: 'error',
+        title: '连接失败',
+        message: '无法连接到汇率服务器，请检查您的网络设置。',
+        timestamp: Date.now() - 1000 * 60 * 60 * 72, // 3 days ago
+        read: true,
+    }
+];
+
+export const NotificationProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
+    const [notifications, setNotifications] = useState<Notification[]>([]);
+
+    useEffect(() => {
+        const stored = localStorage.getItem(STORAGE_KEY);
+        if (stored) {
+            try {
+                setNotifications(JSON.parse(stored));
+            } catch (e) {
+                console.error('Failed to parse notifications', e);
+                setNotifications(MOCK_NOTIFICATIONS);
+            }
+        } else {
+            setNotifications(MOCK_NOTIFICATIONS);
+            localStorage.setItem(STORAGE_KEY, JSON.stringify(MOCK_NOTIFICATIONS));
+        }
+    }, []);
+
+    useEffect(() => {
+        if (notifications.length > 0) {
+            localStorage.setItem(STORAGE_KEY, JSON.stringify(notifications));
+        }
+    }, [notifications]);
+
+    const unreadCount = notifications.filter(n => !n.read).length;
+
+    const markAsRead = useCallback((id: string) => {
+        setNotifications(prev => prev.map(n => n.id === id ? { ...n, read: true } : n));
+    }, []);
+
+    const markAllAsRead = useCallback(() => {
+        setNotifications(prev => prev.map(n => ({ ...n, read: true })));
+    }, []);
+
+    const deleteNotification = useCallback((id: string) => {
+        setNotifications(prev => prev.filter(n => n.id !== id));
+    }, []);
+
+    const addNotification = useCallback((n: Omit<Notification, 'id' | 'timestamp' | 'read'>) => {
+        const newNotification: Notification = {
+            ...n,
+            id: Date.now().toString(),
+            timestamp: Date.now(),
+            read: false,
+        };
+        setNotifications(prev => [newNotification, ...prev]);
+    }, []);
+
+    return (
+        <NotificationContext.Provider value={{
+            notifications,
+            unreadCount,
+            markAsRead,
+            markAllAsRead,
+            deleteNotification,
+            addNotification
+        }}>
+            {children}
+        </NotificationContext.Provider>
+    );
+};
+
+export const useNotifications = () => {
+    const context = useContext(NotificationContext);
+    if (!context) {
+        throw new Error('useNotifications must be used within a NotificationProvider');
+    }
+    return context;
+};