feat(app): 初始化自动关机工具首个版本

实现基于 WPF 的 AutoShutdown 主界面，支持关机、重启、睡眠、休眠、唤醒、锁屏和注销等电源任务。

支持指定时间和倒计时计划、执行前提醒、系统关机撤销、Windows 唤醒任务、托盘运行、自定义图标以及 OmniNotify 通知适配。

修复关闭到托盘时的运行提醒，并支持单击托盘图标打开或收起主界面。

补充 README、发布配置和 win-x64 Release 输出要求。

Release: win-x64

Services/NotificationSettingsStore.cs

@@ -0,0 +1,38 @@
+using System.IO;
+using System.Text.Json;
+using AutoShutdown.Models;
+
+namespace AutoShutdown.Services;
+
+internal sealed class NotificationSettingsStore
+{
+    private readonly string _path = Path.Combine(
+        Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
+        "AutoShutdown",
+        "notification-settings.json");
+
+    public NotificationSettings Load()
+    {
+        try
+        {
+            if (!File.Exists(_path))
+            {
+                return NotificationSettings.Default();
+            }
+
+            var json = File.ReadAllText(_path);
+            return JsonSerializer.Deserialize<NotificationSettings>(json) ?? NotificationSettings.Default();
+        }
+        catch
+        {
+            return NotificationSettings.Default();
+        }
+    }
+
+    public void Save(NotificationSettings settings)
+    {
+        Directory.CreateDirectory(Path.GetDirectoryName(_path)!);
+        var json = JsonSerializer.Serialize(settings, new JsonSerializerOptions { WriteIndented = true });
+        File.WriteAllText(_path, json);
+    }
+}