feat: v1.2.0 开发进度更新

### 新增功能
- **Linux 官方支持**：新增 Hua.Todo.Avalonia 项目，正式适配 Linux 平台，同时支持 Windows 和 macOS
- **Avalonia 桌面交互**：增加托盘菜单（显示/退出）、关闭隐藏到托盘、Windows 全局热键唤起主窗口、热键配置本地持久化
- **SQLite DateTime 兼容修复**：新增 LenientUtcDateTimeStringConverter，解决历史遗留的 DateTime 脏数据解析问题
- **用户文档完善**：新增 docs/manual/新手指南.md 和 docs/manual/用户指南.md
- **部署文档**：新增 docs/manual/部署文档.md，详细说明多平台发布流程

### 优化与修复
- **发布脚本整理**：拆分/对齐各平台发布入口，新增 publish.ps1 作为统一入口
- **Windows WebView2 优化**：数据目录调整到 %LocalAppData%\Hua.Todo\WebView2，修复 Runtime 误判问题
- **MAUI 多平台构建**：在 Windows 开发机上默认仅构建 Android + Windows 目标
- **SPA 路由回落**：修复 Release 模式下 /swagger 路径的 404 问题
- **Swagger 输出**：补齐 Dynamic API 端点，避免接口缺失

### 文档更新
- **版本记录**：更新 v1.2.0 开发进度和功能列表
- **技术设计文档**：添加 Avalonia 项目架构和模块设计
- **项目结构**：更新 README.md 中的项目结构说明

### 其他变更
- 新增 Directory.Build.props 和更新 Directory.Build.targets
- 调整 src/Hua.Todo.Avalonia 项目配置和资源文件
- 更新 src/Hua.Todo.Web 前端资源文件
- 修复 src/Hua.Todo.Maui 相关配置和打包脚本

src/Hua.Todo.Avalonia/App.axaml.cs

@@ -1,8 +1,8 @@
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Controls.ApplicationLifetimes;
-using Avalonia.Data.Core.Plugins;
 using Avalonia.Markup.Xaml;
+using Avalonia.Platform;
 using Avalonia.Threading;
 using AvaloniaWebView;
 using Hua.Todo.Avalonia.Models;
@@ -13,7 +13,6 @@ using Hua.Todo.Avalonia.Views;
 using System;
 using System.ComponentModel;
 using System.IO;
-using System.Linq;
 using System.Text.Json;
 using System.Threading.Tasks;
 
@@ -98,9 +97,7 @@ public partial class App : global::Avalonia.Application
     {
         if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
         {
-            DisableAvaloniaDataAnnotationValidation();
-
-            _webServer = new EmbeddedWebServerService(_appSettings!);
+            _webServer = EmbeddedWebServerServiceFactory.Create(_appSettings!);
             _ = Task.Run(async () =>
             {
                 try
@@ -132,10 +129,16 @@ public partial class App : global::Avalonia.Application
                 };
             }
 
-            DataContext = new AppTrayViewModel(
-                AppMetadata.GetTrayTooltipText(),
-                ShowMainWindow,
-                () => ExitApplication(desktop));
+            // 只在支持的平台上初始化系统托盘
+            if (OperatingSystem.IsWindows() || OperatingSystem.IsLinux())
+            {
+                var trayViewModel = new AppTrayViewModel(
+                    AppMetadata.GetTrayTooltipText(),
+                    ShowMainWindow,
+                    () => ExitApplication(desktop));
+
+                InitializeTrayIcon(trayViewModel);
+            }
 
             _mainWindow = new MainWindow(_appSettings!, _webServer)
             {
@@ -185,6 +188,12 @@ public partial class App : global::Avalonia.Application
                 }
             };
         }
+        else if (ApplicationLifetime is ISingleViewApplicationLifetime singleView)
+        {
+            _webServer = EmbeddedWebServerServiceFactory.Create(_appSettings!);
+
+            singleView.MainView = new MainView(_appSettings!, _webServer);
+        }
 
         base.OnFrameworkInitializationCompleted();
     }
@@ -257,14 +266,43 @@ public partial class App : global::Avalonia.Application
         }
     }
 
-    private void DisableAvaloniaDataAnnotationValidation()
+    private void InitializeTrayIcon(AppTrayViewModel trayViewModel)
     {
-        var dataValidationPluginsToRemove =
-            BindingPlugins.DataValidators.OfType<DataAnnotationsValidationPlugin>().ToArray();
-
-        foreach (var plugin in dataValidationPluginsToRemove)
+        try
         {
-            BindingPlugins.DataValidators.Remove(plugin);
+            var trayIcons = new TrayIcons();
+
+            var iconUri = new Uri("avares://Hua.Todo.Avalonia/Assets/avalonia-logo.ico");
+            var icon = new WindowIcon(AssetLoader.Open(iconUri));
+
+            var trayIcon = new TrayIcon
+            {
+                Icon = icon,
+                ToolTipText = trayViewModel.TrayTooltipText,
+                Command = trayViewModel.ShowMainWindowCommand
+            };
+
+            var menu = new NativeMenu();
+            menu.Items.Add(new NativeMenuItem
+            {
+                Header = "显示主窗口",
+                Command = trayViewModel.ShowMainWindowCommand
+            });
+            menu.Items.Add(new NativeMenuItemSeparator());
+            menu.Items.Add(new NativeMenuItem
+            {
+                Header = "退出",
+                Command = trayViewModel.ExitApplicationCommand
+            });
+
+            trayIcon.Menu = menu;
+            trayIcons.Add(trayIcon);
+
+            TrayIcon.SetIcons(this, trayIcons);
+        }
+        catch (Exception ex)
+        {
+            Console.WriteLine($"[App] Tray icon initialization failed: {ex}");
         }
     }
 }