0.5.15

市场插件安装机制修复，然后修复了一大堆东西

LanAirApp/samples/LanMountainDesktop.SamplePlugin/Localization/en-US.json

@@ -67,6 +67,11 @@
   "capability.message_bus.detail": "This sample plugin uses IPluginMessageBus to push clock ticks and state change notifications into plugin UI surfaces.",
   "capability.widget_context.title": "PluginDesktopComponentContext",
   "capability.widget_context.detail": "Widgets can read ComponentId, PlacementId, CellSize, and call GetService<T>() against the same plugin service container.",
+  "widget.close_desktop.display_name": "Close Desktop",
+  "widget.close_desktop.text": "Close Desktop",
+  "widget.close_desktop.hint": "Exit LanMountainDesktop on click",
+  "widget.close_desktop.unavailable": "Host lifecycle API is unavailable",
+  "widget.close_desktop.failed": "Host rejected the exit request",
   "widget.subtitle.preview": "Preview surface | placed: {0}",
   "widget.subtitle.placement": "Placement {0} | placed: {1}",
   "common.dev": "dev",

LanAirApp/samples/LanMountainDesktop.SamplePlugin/SamplePlugin.cs

@@ -16,6 +16,7 @@ public sealed class SamplePlugin : PluginBase, IDisposable
         var hostName = GetHostProperty(context, PluginHostPropertyKeys.HostApplicationName, "UnknownHost");
         var hostVersion = GetHostProperty(context, PluginHostPropertyKeys.HostVersion, "UnknownVersion");
         var sdkApiVersion = GetHostProperty(context, PluginHostPropertyKeys.PluginSdkApiVersion, "UnknownApiVersion");
+        var hostApplicationLifecycle = context.GetService<IHostApplicationLifecycle>();
         var messageBus = context.GetService<IPluginMessageBus>()
             ?? throw new InvalidOperationException("Plugin message bus is not available.");
 
@@ -74,6 +75,19 @@ public sealed class SamplePlugin : PluginBase, IDisposable
             allowStatusBarPlacement: false,
             resizeMode: PluginDesktopComponentResizeMode.Proportional,
             cornerRadiusResolver: cellSize => Math.Clamp(cellSize * 0.34, 18, 34)));
+
+        context.RegisterDesktopComponent(new PluginDesktopComponentRegistration(
+            "LanMountainDesktop.SamplePlugin.CloseDesktop",
+            localizer.GetString("widget.close_desktop.display_name", "关闭桌面"),
+            widgetContext => new SamplePluginCloseDesktopWidget(widgetContext),
+            iconKey: "DismissCircle",
+            category: localizer.GetString("widget.category", "鎻掍欢"),
+            minWidthCells: 2,
+            minHeightCells: 1,
+            allowDesktopPlacement: true,
+            allowStatusBarPlacement: false,
+            resizeMode: PluginDesktopComponentResizeMode.Free,
+            cornerRadiusResolver: cellSize => Math.Clamp(cellSize * 0.28, 14, 22)));
     }
 
     public void Dispose()

LanAirApp/samples/LanMountainDesktop.SamplePlugin/SamplePluginCloseDesktopWidget.cs

@@ -0,0 +1,166 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Layout;
+using Avalonia.Media;
+using LanMountainDesktop.PluginSdk;
+
+namespace LanMountainDesktop.SamplePlugin;
+
+internal sealed class SamplePluginCloseDesktopWidget : Border
+{
+    private readonly PluginLocalizer _localizer;
+    private readonly IHostApplicationLifecycle? _hostApplicationLifecycle;
+    private readonly TextBlock _titleTextBlock;
+    private readonly TextBlock _statusTextBlock;
+
+    public SamplePluginCloseDesktopWidget(PluginDesktopComponentContext context)
+    {
+        _localizer = PluginLocalizer.Create(context);
+        _hostApplicationLifecycle = context.GetService<IHostApplicationLifecycle>();
+
+        _titleTextBlock = new TextBlock
+        {
+            Text = T("widget.close_desktop.text", "关闭桌面"),
+            Foreground = Brushes.White,
+            FontWeight = FontWeight.SemiBold,
+            VerticalAlignment = VerticalAlignment.Center
+        };
+
+        _statusTextBlock = new TextBlock
+        {
+            Text = _hostApplicationLifecycle is null
+                ? T("widget.close_desktop.unavailable", "宿主未提供退出接口")
+                : T("widget.close_desktop.hint", "点击后退出阑山桌面"),
+            Foreground = new SolidColorBrush(Color.Parse("#FFD4E7F6")),
+            VerticalAlignment = VerticalAlignment.Center
+        };
+
+        var contentGrid = new Grid
+        {
+            ColumnDefinitions = new ColumnDefinitions("Auto,*"),
+            ColumnSpacing = 14,
+            VerticalAlignment = VerticalAlignment.Center,
+            Children =
+            {
+                CreateIconShell(),
+                new StackPanel
+                {
+                    Spacing = 2,
+                    VerticalAlignment = VerticalAlignment.Center,
+                    Children =
+                    {
+                        _titleTextBlock,
+                        _statusTextBlock
+                    }
+                }
+            }
+        };
+
+        Grid.SetColumn(contentGrid.Children[1], 1);
+
+        var actionButton = new Button
+        {
+            HorizontalAlignment = HorizontalAlignment.Stretch,
+            VerticalAlignment = VerticalAlignment.Stretch,
+            HorizontalContentAlignment = HorizontalAlignment.Stretch,
+            VerticalContentAlignment = VerticalAlignment.Stretch,
+            Background = Brushes.Transparent,
+            BorderThickness = new Thickness(0),
+            Padding = new Thickness(0),
+            IsEnabled = _hostApplicationLifecycle is not null,
+            Content = contentGrid
+        };
+        actionButton.Click += OnButtonClick;
+
+        Background = new LinearGradientBrush
+        {
+            StartPoint = new RelativePoint(0, 0, RelativeUnit.Relative),
+            EndPoint = new RelativePoint(1, 1, RelativeUnit.Relative),
+            GradientStops =
+            [
+                new GradientStop(Color.Parse("#FF0B1220"), 0),
+                new GradientStop(Color.Parse("#FF172554"), 0.55),
+                new GradientStop(Color.Parse("#FF7F1D1D"), 1)
+            ]
+        };
+        BorderBrush = new SolidColorBrush(Color.Parse("#66FB7185"));
+        BorderThickness = new Thickness(1);
+        CornerRadius = new CornerRadius(18);
+        Padding = new Thickness(14, 10);
+        Child = actionButton;
+
+        SizeChanged += OnSizeChanged;
+        ApplyScale();
+    }
+
+    private Border CreateIconShell()
+    {
+        return new Border
+        {
+            Width = 36,
+            Height = 36,
+            CornerRadius = new CornerRadius(999),
+            Background = new SolidColorBrush(Color.Parse("#33F87171")),
+            BorderBrush = new SolidColorBrush(Color.Parse("#88FCA5A5")),
+            BorderThickness = new Thickness(1),
+            VerticalAlignment = VerticalAlignment.Center,
+            Child = new TextBlock
+            {
+                Text = "⏻",
+                FontSize = 18,
+                Foreground = Brushes.White,
+                HorizontalAlignment = HorizontalAlignment.Center,
+                VerticalAlignment = VerticalAlignment.Center,
+                TextAlignment = TextAlignment.Center
+            }
+        };
+    }
+
+    private void OnButtonClick(object? sender, Avalonia.Interactivity.RoutedEventArgs e)
+    {
+        if (_hostApplicationLifecycle?.TryExit(new HostApplicationLifecycleRequest(
+                Source: "SamplePlugin.CloseDesktopWidget",
+                Reason: "User invoked the sample plugin close-desktop widget.")) == true)
+        {
+            return;
+        }
+
+        _statusTextBlock.Text = T("widget.close_desktop.failed", "宿主未接受退出请求");
+    }
+
+    private void OnSizeChanged(object? sender, SizeChangedEventArgs e)
+    {
+        ApplyScale();
+    }
+
+    private void ApplyScale()
+    {
+        var basis = Bounds.Height > 1 ? Bounds.Height : 72;
+        Padding = new Thickness(Math.Clamp(basis * 0.18, 12, 18), Math.Clamp(basis * 0.14, 8, 14));
+        CornerRadius = new CornerRadius(Math.Clamp(basis * 0.32, 16, 24));
+
+        if (Child is not Button actionButton || actionButton.Content is not Grid contentGrid)
+        {
+            return;
+        }
+
+        if (contentGrid.Children[0] is Border iconShell)
+        {
+            var iconSize = Math.Clamp(basis * 0.58, 28, 40);
+            iconShell.Width = iconSize;
+            iconShell.Height = iconSize;
+            if (iconShell.Child is TextBlock iconText)
+            {
+                iconText.FontSize = Math.Clamp(iconSize * 0.5, 14, 20);
+            }
+        }
+
+        _titleTextBlock.FontSize = Math.Clamp(basis * 0.28, 14, 20);
+        _statusTextBlock.FontSize = Math.Clamp(basis * 0.18, 10, 13);
+    }
+
+    private string T(string key, string fallback)
+    {
+        return _localizer.GetString(key, fallback);
+    }
+}

LanMountainDesktop.PluginSdk/IHostApplicationLifecycle.cs

@@ -0,0 +1,12 @@
+namespace LanMountainDesktop.PluginSdk;
+
+public sealed record HostApplicationLifecycleRequest(
+    string? Source = null,
+    string? Reason = null);
+
+public interface IHostApplicationLifecycle
+{
+    bool TryExit(HostApplicationLifecycleRequest? request = null);
+
+    bool TryRestart(HostApplicationLifecycleRequest? request = null);
+}

LanMountainDesktop.PluginsInstallHelper/LanMountainDesktop.PluginsInstallHelper.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk" TreatAsLocalProperty="Version;PackageVersion;InformationalVersion;AssemblyVersion;FileVersion">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Version>1.0.0</Version>
+    <PackageVersion>$(Version)</PackageVersion>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\LanMountainDesktop.PluginSdk\LanMountainDesktop.PluginSdk.csproj" />
+  </ItemGroup>
+</Project>

LanMountainDesktop.PluginsInstallHelper/Program.cs

@@ -0,0 +1,242 @@
+using System.IO.Compression;
+using System.Security.Cryptography;
+using System.Text;
+using System.Text.Json;
+using LanMountainDesktop.PluginSdk;
+
+internal static class Program
+{
+    private static readonly TimeSpan[] RetryDelays =
+    [
+        TimeSpan.FromMilliseconds(120),
+        TimeSpan.FromMilliseconds(250),
+        TimeSpan.FromMilliseconds(500)
+    ];
+
+    private static async Task<int> Main(string[] args)
+    {
+        var result = new HelperResult();
+        string? resultPath = null;
+
+        try
+        {
+            var parsedArgs = ParseArgs(args);
+            if (!parsedArgs.TryGetValue("source", out var sourcePath) ||
+                !parsedArgs.TryGetValue("plugins-dir", out var pluginsDirectory) ||
+                !parsedArgs.TryGetValue("result", out resultPath) ||
+                string.IsNullOrWhiteSpace(sourcePath) ||
+                string.IsNullOrWhiteSpace(pluginsDirectory) ||
+                string.IsNullOrWhiteSpace(resultPath))
+            {
+                throw new InvalidOperationException("Required arguments: --source <path> --plugins-dir <path> --result <path>.");
+            }
+
+            var fullSourcePath = Path.GetFullPath(sourcePath);
+            var fullPluginsDirectory = Path.GetFullPath(pluginsDirectory);
+            resultPath = Path.GetFullPath(resultPath);
+
+            if (!File.Exists(fullSourcePath))
+            {
+                throw new FileNotFoundException($"Plugin package '{fullSourcePath}' was not found.", fullSourcePath);
+            }
+
+            var manifest = ReadManifestFromPackage(fullSourcePath);
+            Directory.CreateDirectory(fullPluginsDirectory);
+            var destinationPath = Path.Combine(fullPluginsDirectory, BuildInstalledPackageFileName(manifest.Id));
+            var stagingPath = destinationPath + ".incoming";
+            DeleteFileWithRetry(stagingPath);
+            CopyWithRetry(fullSourcePath, stagingPath, overwrite: true);
+            RemoveExistingPluginPackages(fullPluginsDirectory, manifest.Id, destinationPath, stagingPath);
+            MoveWithOverwriteRetry(stagingPath, destinationPath);
+
+            result = new HelperResult
+            {
+                Success = true,
+                InstalledPackagePath = destinationPath,
+                ManifestId = manifest.Id,
+                ManifestName = manifest.Name
+            };
+        }
+        catch (Exception ex)
+        {
+            result = new HelperResult
+            {
+                Success = false,
+                ErrorMessage = ex.Message
+            };
+        }
+
+        if (!string.IsNullOrWhiteSpace(resultPath))
+        {
+            var resultDirectory = Path.GetDirectoryName(resultPath);
+            if (!string.IsNullOrWhiteSpace(resultDirectory))
+            {
+                Directory.CreateDirectory(resultDirectory);
+            }
+
+            await File.WriteAllTextAsync(
+                resultPath,
+                JsonSerializer.Serialize(result, new JsonSerializerOptions
+                {
+                    WriteIndented = true
+                }),
+                Encoding.UTF8);
+        }
+
+        return result.Success ? 0 : 1;
+    }
+
+    private static Dictionary<string, string> ParseArgs(string[] args)
+    {
+        var values = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+        for (var i = 0; i < args.Length; i++)
+        {
+            var current = args[i];
+            if (!current.StartsWith("--", StringComparison.Ordinal))
+            {
+                continue;
+            }
+
+            var key = current[2..];
+            if (string.IsNullOrWhiteSpace(key) || i + 1 >= args.Length)
+            {
+                continue;
+            }
+
+            values[key] = args[++i];
+        }
+
+        return values;
+    }
+
+    private static PluginManifest ReadManifestFromPackage(string packagePath)
+    {
+        using var archive = ZipFile.OpenRead(packagePath);
+        var entries = archive.Entries
+            .Where(entry => string.Equals(entry.Name, PluginSdkInfo.ManifestFileName, StringComparison.OrdinalIgnoreCase))
+            .ToArray();
+
+        if (entries.Length == 0)
+        {
+            throw new InvalidOperationException(
+                $"Plugin package '{packagePath}' does not contain '{PluginSdkInfo.ManifestFileName}'.");
+        }
+
+        if (entries.Length > 1)
+        {
+            throw new InvalidOperationException(
+                $"Plugin package '{packagePath}' contains multiple '{PluginSdkInfo.ManifestFileName}' files.");
+        }
+
+        using var stream = entries[0].Open();
+        return PluginManifest.Load(stream, $"{packagePath}!/{entries[0].FullName}");
+    }
+
+    private static void RemoveExistingPluginPackages(string pluginsDirectory, string pluginId, string destinationPath, string stagingPath)
+    {
+        var runtimeRootDirectory = EnsureTrailingSeparator(Path.Combine(Path.GetFullPath(pluginsDirectory), PluginSdkInfo.RuntimeDirectoryName));
+        foreach (var existingPackagePath in Directory
+                     .EnumerateFiles(pluginsDirectory, "*" + PluginSdkInfo.PackageFileExtension, SearchOption.AllDirectories)
+                     .Select(Path.GetFullPath)
+                     .Where(path => !path.StartsWith(runtimeRootDirectory, StringComparison.OrdinalIgnoreCase)))
+        {
+            try
+            {
+                if (string.Equals(existingPackagePath, Path.GetFullPath(destinationPath), StringComparison.OrdinalIgnoreCase) ||
+                    string.Equals(existingPackagePath, Path.GetFullPath(stagingPath), StringComparison.OrdinalIgnoreCase))
+                {
+                    continue;
+                }
+
+                var existingManifest = ReadManifestFromPackage(existingPackagePath);
+                if (!string.Equals(existingManifest.Id, pluginId, StringComparison.OrdinalIgnoreCase))
+                {
+                    continue;
+                }
+
+                DeleteFileWithRetry(existingPackagePath);
+            }
+            catch
+            {
+                // Ignore unrelated or malformed packages while replacing an install target.
+            }
+        }
+    }
+
+    private static void CopyWithRetry(string sourcePath, string destinationPath, bool overwrite)
+    {
+        Retry(() => File.Copy(sourcePath, destinationPath, overwrite));
+    }
+
+    private static void MoveWithOverwriteRetry(string sourcePath, string destinationPath)
+    {
+        Retry(() => File.Move(sourcePath, destinationPath, overwrite: true));
+    }
+
+    private static void DeleteFileWithRetry(string filePath)
+    {
+        Retry(() =>
+        {
+            if (File.Exists(filePath))
+            {
+                File.Delete(filePath);
+            }
+        });
+    }
+
+    private static void Retry(Action action)
+    {
+        Exception? lastException = null;
+
+        for (var attempt = 0; attempt <= RetryDelays.Length; attempt++)
+        {
+            try
+            {
+                action();
+                return;
+            }
+            catch (Exception ex) when (ex is IOException or UnauthorizedAccessException)
+            {
+                lastException = ex;
+                if (attempt >= RetryDelays.Length)
+                {
+                    break;
+                }
+
+                Thread.Sleep(RetryDelays[attempt]);
+            }
+        }
+
+        if (lastException is not null)
+        {
+            throw lastException;
+        }
+    }
+
+    private static string BuildInstalledPackageFileName(string pluginId)
+    {
+        var invalidChars = Path.GetInvalidFileNameChars();
+        var fileName = new string(pluginId.Select(ch => invalidChars.Contains(ch) ? '_' : ch).ToArray());
+        return fileName + PluginSdkInfo.PackageFileExtension;
+    }
+
+    private static string EnsureTrailingSeparator(string path)
+    {
+        return path.EndsWith(Path.DirectorySeparatorChar.ToString(), StringComparison.Ordinal)
+            ? path
+            : path + Path.DirectorySeparatorChar;
+    }
+
+    private sealed class HelperResult
+    {
+        public bool Success { get; init; }
+
+        public string? InstalledPackagePath { get; init; }
+
+        public string? ManifestId { get; init; }
+
+        public string? ManifestName { get; init; }
+
+        public string? ErrorMessage { get; init; }
+    }
+}

LanMountainDesktop.sln

@@ -11,6 +11,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LanMountainDesktop.PluginPa
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LanMountainDesktop.PluginSdk", "LanMountainDesktop.PluginSdk\LanMountainDesktop.PluginSdk.csproj", "{30A0F689-AACC-48C8-8BFE-BC7BFBA6CC55}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LanMountainDesktop.PluginsInstallHelper", "LanMountainDesktop.PluginsInstallHelper\LanMountainDesktop.PluginsInstallHelper.csproj", "{5A20D5E9-BD27-4DD4-9F4F-97E0367DD2AC}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -33,5 +35,9 @@ Global
 		{30A0F689-AACC-48C8-8BFE-BC7BFBA6CC55}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{30A0F689-AACC-48C8-8BFE-BC7BFBA6CC55}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{30A0F689-AACC-48C8-8BFE-BC7BFBA6CC55}.Release|Any CPU.Build.0 = Release|Any CPU
+		{5A20D5E9-BD27-4DD4-9F4F-97E0367DD2AC}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{5A20D5E9-BD27-4DD4-9F4F-97E0367DD2AC}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{5A20D5E9-BD27-4DD4-9F4F-97E0367DD2AC}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{5A20D5E9-BD27-4DD4-9F4F-97E0367DD2AC}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 EndGlobal

LanMountainDesktop/App.axaml.cs

@@ -12,6 +12,7 @@ using LanMountainDesktop.Services;
 using LanMountainDesktop.ViewModels;
 using LanMountainDesktop.Views;
 using AvaloniaWebView;
+using LanMountainDesktop.PluginSdk;
 
 namespace LanMountainDesktop;
 
@@ -19,12 +20,19 @@ public partial class App : Application
 {
     private readonly AppSettingsService _appSettingsService = new();
     private readonly LocalizationService _localizationService = new();
+    private readonly IHostApplicationLifecycle _hostApplicationLifecycle = new HostApplicationLifecycleService();
+    private bool _exitCleanupCompleted;
 
     private SettingsWindow? _traySettingsWindow;
     private TrayIcons? _trayIcons;
     private PluginRuntimeService? _pluginRuntimeService;
 
+    internal static SingleInstanceService? CurrentSingleInstanceService { get; set; }
+    internal static IHostApplicationLifecycle? CurrentHostApplicationLifecycle =>
+        (Current as App)?._hostApplicationLifecycle;
+
     public PluginRuntimeService? PluginRuntimeService => _pluginRuntimeService;
+    public IHostApplicationLifecycle HostApplicationLifecycle => _hostApplicationLifecycle;
 
     public override void Initialize()
     {
@@ -51,14 +59,14 @@ public partial class App : Application
             desktop.Exit += (_, _) =>
             {
                 AppLogger.Info("App", "Desktop lifetime exit triggered.");
-                AppSettingsService.SettingsSaved -= OnAppSettingsSaved;
-                DisposeTrayIcon();
+                PerformExitCleanup();
             };
             desktop.MainWindow = new MainWindow
             {
                 DataContext = new MainWindowViewModel(),
             };
             AppLogger.Info("App", $"Main window created. LogFile={AppLogger.LogFilePath}");
+            CurrentSingleInstanceService?.StartActivationListener(ActivateMainWindow);
         }
 
         base.OnFrameworkInitializationCompleted();
@@ -66,12 +74,9 @@ public partial class App : Application
 
     private void OnTrayExitClick(object? sender, EventArgs e)
     {
-        DisposeTrayIcon();
-
-        if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
-        {
-            desktop.Shutdown();
-        }
+        _ = _hostApplicationLifecycle.TryExit(new HostApplicationLifecycleRequest(
+            Source: "TrayMenu",
+            Reason: "User selected Exit App from the tray menu."));
     }
 
     private void OnTraySettingsClick(object? sender, EventArgs e)
@@ -114,18 +119,9 @@ public partial class App : Application
 
     private void OnTrayRestartClick(object? sender, EventArgs e)
     {
-        AppRestartService.TryRestartApplication();
-    }
-
-    private void OnAppSettingsSaved(string _)
-    {
-        Dispatcher.UIThread.Post(() =>
-        {
-            if (_trayIcons is not null)
-            {
-                InitializeTrayIcon();
-            }
-        }, DispatcherPriority.Background);
+        _ = _hostApplicationLifecycle.TryRestart(new HostApplicationLifecycleRequest(
+            Source: "TrayMenu",
+            Reason: "User selected Restart App from the tray menu."));
     }
 
     private void DisableAvaloniaDataAnnotationValidation()
@@ -246,6 +242,99 @@ public partial class App : Application
         _trayIcons = null;
     }
 
+    private void ActivateMainWindow()
+    {
+        Dispatcher.UIThread.Post(() =>
+        {
+            if (ApplicationLifetime is not IClassicDesktopStyleApplicationLifetime desktop)
+            {
+                return;
+            }
+
+            if (desktop.MainWindow is not Window mainWindow)
+            {
+                return;
+            }
+
+            try
+            {
+                if (!mainWindow.IsVisible)
+                {
+                    mainWindow.Show();
+                }
+
+                if (mainWindow.WindowState == WindowState.Minimized)
+                {
+                    mainWindow.WindowState = WindowState.Normal;
+                }
+
+                mainWindow.Activate();
+                mainWindow.Topmost = true;
+                mainWindow.Topmost = false;
+                if (mainWindow is MainWindow lanMountainMainWindow)
+                {
+                    lanMountainMainWindow.ShowSingleInstanceNotice();
+                }
+            }
+            catch (Exception ex)
+            {
+                AppLogger.Warn("SingleInstance", "Failed to activate the existing main window.", ex);
+            }
+        }, DispatcherPriority.Send);
+    }
+
+    private void OnAppSettingsSaved(string _)
+    {
+        Dispatcher.UIThread.Post(() =>
+        {
+            if (_trayIcons is not null)
+            {
+                InitializeTrayIcon();
+            }
+        }, DispatcherPriority.Background);
+    }
+
+    private void PerformExitCleanup()
+    {
+        if (_exitCleanupCompleted)
+        {
+            return;
+        }
+
+        _exitCleanupCompleted = true;
+        AppSettingsService.SettingsSaved -= OnAppSettingsSaved;
+
+        try
+        {
+            _traySettingsWindow?.Close();
+        }
+        catch (Exception ex)
+        {
+            AppLogger.Warn("App", "Failed to close tray-opened settings window during shutdown.", ex);
+        }
+        finally
+        {
+            _traySettingsWindow = null;
+        }
+
+        try
+        {
+            _pluginRuntimeService?.Dispose();
+        }
+        catch (Exception ex)
+        {
+            AppLogger.Warn("PluginRuntime", "Failed to dispose plugin runtime during shutdown.", ex);
+        }
+        finally
+        {
+            _pluginRuntimeService = null;
+        }
+
+        AudioRecorderServiceFactory.DisposeSharedServices();
+        StudyAnalyticsServiceFactory.DisposeSharedService();
+        DisposeTrayIcon();
+    }
+
     private string L(string key, string fallback)
     {
         var snapshot = _appSettingsService.Load();

LanMountainDesktop/LanMountainDesktop.csproj

@@ -26,6 +26,8 @@
 
   <ItemGroup>
     <ProjectReference Include="..\LanMountainDesktop.PluginSdk\LanMountainDesktop.PluginSdk.csproj" />
+    <ProjectReference Include="..\LanMountainDesktop.PluginsInstallHelper\LanMountainDesktop.PluginsInstallHelper.csproj"
+                      ReferenceOutputAssembly="false" />
   </ItemGroup>
 
   <ItemGroup>
@@ -56,4 +58,22 @@
     <PackageReference Include="WebView.Avalonia.Desktop" Version="11.0.0.1" />
     <PackageReference Include="YamlDotNet" Version="16.3.0" />
   </ItemGroup>
+
+  <Target Name="CopyPluginsInstallHelperToOutput" AfterTargets="Build">
+    <ItemGroup>
+      <PluginsInstallHelperFiles Include="..\LanMountainDesktop.PluginsInstallHelper\bin\$(Configuration)\net10.0\**\*.*" />
+    </ItemGroup>
+    <Copy SourceFiles="@(PluginsInstallHelperFiles)"
+          DestinationFiles="@(PluginsInstallHelperFiles->'$(OutDir)PluginsInstallHelper\%(RecursiveDir)%(Filename)%(Extension)')"
+          SkipUnchangedFiles="true" />
+  </Target>
+
+  <Target Name="CopyPluginsInstallHelperToPublish" AfterTargets="Publish" Condition="'$(PublishDir)' != ''">
+    <ItemGroup>
+      <PluginsInstallHelperPublishFiles Include="..\LanMountainDesktop.PluginsInstallHelper\bin\$(Configuration)\net10.0\**\*.*" />
+    </ItemGroup>
+    <Copy SourceFiles="@(PluginsInstallHelperPublishFiles)"
+          DestinationFiles="@(PluginsInstallHelperPublishFiles->'$(PublishDir)PluginsInstallHelper\%(RecursiveDir)%(Filename)%(Extension)')"
+          SkipUnchangedFiles="true" />
+  </Target>
 </Project>

LanMountainDesktop/Localization/en-US.json

@@ -251,6 +251,7 @@
     "settings.update.status_launching_installer":  "Download complete. Launching installer...",
     "settings.update.status_installer_missing":  "Installer file was not found after download.",
     "settings.update.status_installer_started":  "Installer started. The app will close for update.",
+    "settings.update.status_elevation_cancelled":  "Administrator permission was not granted. Update was cancelled.",
     "settings.update.status_launch_failed_format":  "Failed to start installer: {0}",
     "settings.about.title":  "About",
     "settings.about.version_format":  "Version: {0}",
@@ -742,7 +743,10 @@
     "placement.fit":  "Fit",
     "placement.stretch":  "Stretch",
     "placement.center":  "Center",
-    "placement.tile":  "Tile"
-}
+    "placement.tile":  "Tile",
+    "single_instance.notice.title":  "App already open",
+    "single_instance.notice.description":  "LanMountainDesktop is already running. Switched back to the active desktop.",
+    "single_instance.notice.button":  "Got it"
+  }
 
 

LanMountainDesktop/Localization/zh-CN.json

@@ -251,6 +251,7 @@
     "settings.update.status_launching_installer":  "下载完成，正在启动安装程序...",
     "settings.update.status_installer_missing":  "下载后未找到安装包文件。",
     "settings.update.status_installer_started":  "安装程序已启动，应用将关闭进行更新。",
+    "settings.update.status_elevation_cancelled":  "未授予管理员权限，更新已取消。",
     "settings.update.status_launch_failed_format":  "启动安装程序失败：{0}",
     "settings.about.title":  "关于",
     "settings.about.version_format":  "版本号: {0}",
@@ -742,7 +743,10 @@
     "placement.fit":  "适应",
     "placement.stretch":  "拉伸",
     "placement.center":  "居中",
-    "placement.tile":  "平铺"
-}
+    "placement.tile":  "平铺",
+    "single_instance.notice.title":  "应用已打开",
+    "single_instance.notice.description":  "阑山桌面已经在运行，已为你切换到当前正在使用的桌面。",
+    "single_instance.notice.button":  "知道了"
+  }
 
 

LanMountainDesktop/Program.cs

@@ -1,8 +1,10 @@
+using System;
+using System.Diagnostics;
+using System.Threading;
+using System.Threading.Tasks;
 using Avalonia;
 using Avalonia.WebView.Desktop;
 using LanMountainDesktop.Services;
-using System;
-using System.Threading.Tasks;
 
 namespace LanMountainDesktop;
 
@@ -17,6 +19,14 @@ sealed class Program
         AppLogger.Initialize();
         RegisterGlobalExceptionLogging();
 
+        using var singleInstance = AcquireSingleInstance(args);
+        if (!singleInstance.IsPrimaryInstance)
+        {
+            AppLogger.Warn("Startup", "A secondary launch was blocked because another instance is already running.");
+            _ = singleInstance.TryNotifyPrimaryInstance(TimeSpan.FromSeconds(2));
+            return;
+        }
+
         var diagnostics = StartupDiagnosticsService.Run(args);
         StartupDiagnosticsService.ShowLegacyExecutableWarningIfNeeded(diagnostics);
 
@@ -24,6 +34,7 @@ sealed class Program
         {
             var renderMode = LoadConfiguredRenderMode();
             AppLogger.Info("Startup", $"Resolved render mode '{renderMode}'.");
+            App.CurrentSingleInstanceService = singleInstance;
             BuildAvaloniaApp(renderMode).StartWithClassicDesktopLifetime(args);
             AppLogger.Info("Startup", "Application exited normally.");
         }
@@ -32,6 +43,10 @@ sealed class Program
             AppLogger.Critical("Startup", "Application terminated during startup.", ex);
             throw;
         }
+        finally
+        {
+            App.CurrentSingleInstanceService = null;
+        }
     }
 
     // Avalonia configuration, don't remove; also used by visual designer.
@@ -58,6 +73,42 @@ sealed class Program
         return builder;
     }
 
+    private static SingleInstanceService AcquireSingleInstance(string[] args)
+    {
+        var restartParentProcessId = AppRestartService.TryGetRestartParentProcessId(args);
+        var singleInstance = SingleInstanceService.CreateDefault();
+        if (singleInstance.IsPrimaryInstance || restartParentProcessId is null)
+        {
+            return singleInstance;
+        }
+
+        AppLogger.Info(
+            "Startup",
+            $"Restart relaunch detected. Waiting for previous instance pid={restartParentProcessId.Value} to exit before re-acquiring the single-instance lock.");
+        singleInstance.Dispose();
+
+        var deadline = DateTime.UtcNow + TimeSpan.FromSeconds(12);
+        WaitForRestartParentExit(restartParentProcessId.Value, deadline);
+
+        while (DateTime.UtcNow < deadline)
+        {
+            var retryInstance = SingleInstanceService.CreateDefault();
+            if (retryInstance.IsPrimaryInstance)
+            {
+                AppLogger.Info("Startup", "Restart relaunch acquired the single-instance lock.");
+                return retryInstance;
+            }
+
+            retryInstance.Dispose();
+            Thread.Sleep(150);
+        }
+
+        AppLogger.Warn(
+            "Startup",
+            $"Restart relaunch timed out while waiting for the single-instance lock. pid={restartParentProcessId.Value}.");
+        return SingleInstanceService.CreateDefault();
+    }
+
     private static string LoadConfiguredRenderMode()
     {
         try
@@ -71,6 +122,27 @@ sealed class Program
         }
     }
 
+    private static void WaitForRestartParentExit(int processId, DateTime deadlineUtc)
+    {
+        try
+        {
+            using var process = Process.GetProcessById(processId);
+            var remaining = deadlineUtc - DateTime.UtcNow;
+            if (remaining > TimeSpan.Zero)
+            {
+                process.WaitForExit((int)Math.Ceiling(remaining.TotalMilliseconds));
+            }
+        }
+        catch (ArgumentException)
+        {
+            // The previous process already exited before we started waiting.
+        }
+        catch (Exception ex)
+        {
+            AppLogger.Warn("Startup", $"Failed while waiting for restart parent pid={processId} to exit.", ex);
+        }
+    }
+
     private static void RegisterGlobalExceptionLogging()
     {
         AppDomain.CurrentDomain.UnhandledException += (_, eventArgs) =>

LanMountainDesktop/Services/AppRestartService.cs

@@ -3,26 +3,19 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
 using System.Reflection;
-using Avalonia;
-using Avalonia.Controls.ApplicationLifetimes;
+using LanMountainDesktop.PluginSdk;
 
 namespace LanMountainDesktop.Services;
 
 public static class AppRestartService
 {
+    private const string RestartParentPidArgumentPrefix = "--restart-parent-pid=";
+
     public static bool TryRestartApplication()
     {
-        if (!TryRestartCurrentProcess())
-        {
-            return false;
-        }
-
-        if (Application.Current?.ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
-        {
-            desktop.Shutdown();
-        }
-
-        return true;
+        return App.CurrentHostApplicationLifecycle?.TryRestart(new HostApplicationLifecycleRequest(
+            Source: nameof(AppRestartService),
+            Reason: "Legacy restart entry point invoked.")) == true;
     }
 
     public static bool TryRestartCurrentProcess()
@@ -84,6 +77,21 @@ public static class AppRestartService
         return null;
     }
 
+    public static int? TryGetRestartParentProcessId(IReadOnlyList<string> commandLineArgs)
+    {
+        ArgumentNullException.ThrowIfNull(commandLineArgs);
+
+        foreach (var argument in commandLineArgs)
+        {
+            if (TryParseRestartParentProcessId(argument, out var processId))
+            {
+                return processId;
+            }
+        }
+
+        return null;
+    }
+
     private static ProcessStartInfo CreateExecutableStartInfo(
         string executablePath,
         string? entryAssemblyPath,
@@ -97,6 +105,7 @@ public static class AppRestartService
         };
 
         AppendArguments(startInfo, commandLineArgs);
+        AppendRestartParentProcessArgument(startInfo);
         return startInfo;
     }
 
@@ -119,6 +128,7 @@ public static class AppRestartService
 
         startInfo.ArgumentList.Add(entryAssemblyPath);
         AppendArguments(startInfo, commandLineArgs);
+        AppendRestartParentProcessArgument(startInfo);
         return startInfo;
     }
 
@@ -126,10 +136,34 @@ public static class AppRestartService
     {
         for (var i = 1; i < commandLineArgs.Count; i++)
         {
+            if (TryParseRestartParentProcessId(commandLineArgs[i], out _))
+            {
+                continue;
+            }
+
             startInfo.ArgumentList.Add(commandLineArgs[i]);
         }
     }
 
+    private static void AppendRestartParentProcessArgument(ProcessStartInfo startInfo)
+    {
+        startInfo.ArgumentList.Add($"{RestartParentPidArgumentPrefix}{Environment.ProcessId}");
+    }
+
+    private static bool TryParseRestartParentProcessId(string? argument, out int processId)
+    {
+        processId = 0;
+        if (string.IsNullOrWhiteSpace(argument) ||
+            !argument.StartsWith(RestartParentPidArgumentPrefix, StringComparison.OrdinalIgnoreCase))
+        {
+            return false;
+        }
+
+        return int.TryParse(
+            argument[RestartParentPidArgumentPrefix.Length..],
+            out processId) && processId > 0;
+    }
+
     private static string? NormalizeExistingPath(string? path)
     {
         if (string.IsNullOrWhiteSpace(path))

LanMountainDesktop/Services/HostApplicationLifecycleService.cs

@@ -0,0 +1,75 @@
+using System;
+using System.Diagnostics;
+using Avalonia;
+using Avalonia.Controls.ApplicationLifetimes;
+using Avalonia.Threading;
+using LanMountainDesktop.PluginSdk;
+
+namespace LanMountainDesktop.Services;
+
+public sealed class HostApplicationLifecycleService : IHostApplicationLifecycle
+{
+    public bool TryExit(HostApplicationLifecycleRequest? request = null)
+    {
+        try
+        {
+            AppLogger.Info(
+                "HostLifecycle",
+                $"Exit requested. Source='{request?.Source ?? "Unknown"}'; Reason='{request?.Reason ?? string.Empty}'.");
+
+            if (Application.Current?.ApplicationLifetime is not IClassicDesktopStyleApplicationLifetime desktop)
+            {
+                AppLogger.Warn("HostLifecycle", "Exit request ignored because desktop lifetime is unavailable.");
+                return false;
+            }
+
+            if (Dispatcher.UIThread.CheckAccess())
+            {
+                desktop.Shutdown();
+            }
+            else
+            {
+                Dispatcher.UIThread.Post(() => desktop.Shutdown(), DispatcherPriority.Send);
+            }
+
+            return true;
+        }
+        catch (Exception ex)
+        {
+            AppLogger.Warn("HostLifecycle", "Failed to exit the application.", ex);
+            return false;
+        }
+    }
+
+    public bool TryRestart(HostApplicationLifecycleRequest? request = null)
+    {
+        try
+        {
+            var startInfo = AppRestartService.CreateRestartStartInfo();
+            if (startInfo is null)
+            {
+                AppLogger.Warn(
+                    "HostLifecycle",
+                    $"Restart request rejected because restart start info could not be resolved. Source='{request?.Source ?? "Unknown"}'.");
+                return false;
+            }
+
+            Process.Start(startInfo);
+            var exitRequest = request is null
+                ? new HostApplicationLifecycleRequest(Reason: "Restart accepted.")
+                : request with
+                {
+                    Reason = string.IsNullOrWhiteSpace(request.Reason)
+                        ? "Restart accepted."
+                        : request.Reason
+                };
+
+            return TryExit(exitRequest);
+        }
+        catch (Exception ex)
+        {
+            AppLogger.Warn("HostLifecycle", "Failed to restart the application.", ex);
+            return false;
+        }
+    }
+}

LanMountainDesktop/Services/IAudioRecorderService.cs

@@ -80,6 +80,19 @@ public static class AudioRecorderServiceFactory
     {
         return CreateRecorder();
     }
+
+    public static void DisposeSharedServices()
+    {
+        if (SharedRecorderService.IsValueCreated)
+        {
+            SharedRecorderService.Value.Dispose();
+        }
+
+        if (SharedStudyMonitoringService.IsValueCreated)
+        {
+            SharedStudyMonitoringService.Value.Dispose();
+        }
+    }
 }
 
 internal sealed class NoOpAudioRecorderService(string reason) : IAudioRecorderService

LanMountainDesktop/Services/PluginsInstallHelperClient.cs

@@ -0,0 +1,186 @@
+using System;
+using System.ComponentModel;
+using System.Diagnostics;
+using System.Globalization;
+using System.IO;
+using System.Text;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace LanMountainDesktop.Services;
+
+internal sealed class PluginsInstallHelperClient
+{
+    private const int UserCanceledUacErrorCode = 1223;
+    private const string HelperExecutableName = "LanMountainDesktop.PluginsInstallHelper.exe";
+
+    public async Task<PluginsInstallHelperResult> InstallPackageAsync(
+        string packagePath,
+        string pluginsDirectory,
+        CancellationToken cancellationToken = default)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(packagePath);
+        ArgumentException.ThrowIfNullOrWhiteSpace(pluginsDirectory);
+
+        if (!OperatingSystem.IsWindows())
+        {
+            return new PluginsInstallHelperResult(
+                false,
+                null,
+                "Elevated helper install is only supported on Windows.");
+        }
+
+        var helperPath = ResolveHelperPath();
+        if (!File.Exists(helperPath))
+        {
+            return new PluginsInstallHelperResult(
+                false,
+                null,
+                $"Plugins install helper was not found at '{helperPath}'.");
+        }
+
+        var resultPath = Path.Combine(
+            Path.GetTempPath(),
+            "LanMountainDesktop",
+            "PluginInstallResults",
+            $"{Guid.NewGuid():N}.json");
+
+        Directory.CreateDirectory(Path.GetDirectoryName(resultPath)!);
+
+        try
+        {
+            using var process = StartHelperProcess(helperPath, packagePath, pluginsDirectory, resultPath);
+            if (process is null)
+            {
+                return new PluginsInstallHelperResult(false, null, "Failed to start plugins install helper.");
+            }
+
+            await process.WaitForExitAsync(cancellationToken);
+            var result = await ReadResultAsync(resultPath, cancellationToken);
+            if (result is not null)
+            {
+                return new PluginsInstallHelperResult(result.Success, result.InstalledPackagePath, result.ErrorMessage);
+            }
+
+            if (process.ExitCode == 0)
+            {
+                return new PluginsInstallHelperResult(
+                    false,
+                    null,
+                    "Plugins install helper exited without producing a result file.");
+            }
+
+            return new PluginsInstallHelperResult(
+                false,
+                null,
+                string.Format(
+                    CultureInfo.InvariantCulture,
+                    "Plugins install helper exited with code {0}.",
+                    process.ExitCode));
+        }
+        catch (Win32Exception ex) when (ex.NativeErrorCode == UserCanceledUacErrorCode)
+        {
+            return new PluginsInstallHelperResult(false, null, "Administrator permission request was canceled.");
+        }
+        finally
+        {
+            TryDeleteFile(resultPath);
+        }
+    }
+
+    private static Process? StartHelperProcess(
+        string helperPath,
+        string packagePath,
+        string pluginsDirectory,
+        string resultPath)
+    {
+        var startInfo = new ProcessStartInfo
+        {
+            FileName = helperPath,
+            Verb = "runas",
+            UseShellExecute = true,
+            WorkingDirectory = Path.GetDirectoryName(helperPath) ?? AppContext.BaseDirectory,
+            Arguments = string.Create(
+                CultureInfo.InvariantCulture,
+                $"--source {QuoteArgument(Path.GetFullPath(packagePath))} --plugins-dir {QuoteArgument(Path.GetFullPath(pluginsDirectory))} --result {QuoteArgument(Path.GetFullPath(resultPath))}")
+        };
+
+        return Process.Start(startInfo);
+    }
+
+    private static async Task<HelperResultFile?> ReadResultAsync(string resultPath, CancellationToken cancellationToken)
+    {
+        if (!File.Exists(resultPath))
+        {
+            return null;
+        }
+
+        await using var stream = File.OpenRead(resultPath);
+        return await JsonSerializer.DeserializeAsync<HelperResultFile>(stream, cancellationToken: cancellationToken);
+    }
+
+    private static string ResolveHelperPath()
+    {
+        return Path.Combine(AppContext.BaseDirectory, "PluginsInstallHelper", HelperExecutableName);
+    }
+
+    private static string QuoteArgument(string value)
+    {
+        if (string.IsNullOrEmpty(value))
+        {
+            return "\"\"";
+        }
+
+        if (!value.Contains('"') && !value.Contains(' ') && !value.Contains('\t'))
+        {
+            return value;
+        }
+
+        var builder = new StringBuilder();
+        builder.Append('"');
+        foreach (var ch in value)
+        {
+            if (ch == '"')
+            {
+                builder.Append("\\\"");
+            }
+            else
+            {
+                builder.Append(ch);
+            }
+        }
+
+        builder.Append('"');
+        return builder.ToString();
+    }
+
+    private static void TryDeleteFile(string path)
+    {
+        try
+        {
+            if (File.Exists(path))
+            {
+                File.Delete(path);
+            }
+        }
+        catch
+        {
+            // Ignore temp file cleanup failures.
+        }
+    }
+
+    private sealed class HelperResultFile
+    {
+        public bool Success { get; init; }
+
+        public string? InstalledPackagePath { get; init; }
+
+        public string? ErrorMessage { get; init; }
+    }
+}
+
+internal sealed record PluginsInstallHelperResult(
+    bool Success,
+    string? InstalledPackagePath,
+    string? ErrorMessage);

LanMountainDesktop/Services/SingleInstanceService.cs

@@ -0,0 +1,151 @@
+using System;
+using System.IO.Pipes;
+using System.Security.Cryptography;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace LanMountainDesktop.Services;
+
+public sealed class SingleInstanceService : IDisposable
+{
+    private readonly Mutex _mutex;
+    private readonly string _pipeName;
+    private readonly CancellationTokenSource _listenCts = new();
+    private bool _ownsMutex;
+    private bool _disposed;
+    private Task? _listenTask;
+
+    private SingleInstanceService(string mutexName, string pipeName)
+    {
+        _mutex = new Mutex(initiallyOwned: false, mutexName);
+        _pipeName = pipeName;
+        try
+        {
+            _ownsMutex = _mutex.WaitOne(TimeSpan.Zero, exitContext: false);
+        }
+        catch (AbandonedMutexException)
+        {
+            _ownsMutex = true;
+        }
+    }
+
+    public bool IsPrimaryInstance => _ownsMutex;
+
+    public static SingleInstanceService CreateDefault()
+    {
+        const string appId = "LanMountainDesktop";
+        var userName = Environment.UserName;
+        var scopeSeed = $"{appId}:{userName}";
+        var scopeHash = Convert.ToHexString(SHA256.HashData(Encoding.UTF8.GetBytes(scopeSeed)));
+        var suffix = scopeHash[..16];
+        var mutexName = OperatingSystem.IsWindows()
+            ? $"Local\\{appId}.SingleInstance.{suffix}"
+            : $"{appId}.SingleInstance.{suffix}";
+        return new SingleInstanceService(
+            mutexName,
+            $"{appId}.Activate.{suffix}");
+    }
+
+    public void StartActivationListener(Action onActivationRequested)
+    {
+        ArgumentNullException.ThrowIfNull(onActivationRequested);
+
+        if (!_ownsMutex || _disposed || _listenTask is not null)
+        {
+            return;
+        }
+
+        _listenTask = Task.Run(() => ListenForActivationAsync(onActivationRequested, _listenCts.Token));
+    }
+
+    public bool TryNotifyPrimaryInstance(TimeSpan timeout)
+    {
+        if (_ownsMutex || _disposed)
+        {
+            return false;
+        }
+
+        try
+        {
+            using var client = new NamedPipeClientStream(
+                serverName: ".",
+                pipeName: _pipeName,
+                direction: PipeDirection.Out,
+                options: PipeOptions.Asynchronous);
+
+            client.Connect((int)Math.Max(1, timeout.TotalMilliseconds));
+            client.WriteByte(1);
+            client.Flush();
+            return true;
+        }
+        catch (Exception ex)
+        {
+            AppLogger.Warn("SingleInstance", "Failed to notify the primary instance.", ex);
+            return false;
+        }
+    }
+
+    public void Dispose()
+    {
+        if (_disposed)
+        {
+            return;
+        }
+
+        _disposed = true;
+        _listenCts.Cancel();
+        try
+        {
+            _listenTask?.Wait(TimeSpan.FromSeconds(1));
+        }
+        catch
+        {
+            // Ignore listener shutdown races during process exit.
+        }
+
+        _listenCts.Dispose();
+        if (_ownsMutex)
+        {
+            try
+            {
+                _mutex.ReleaseMutex();
+            }
+            catch (ApplicationException)
+            {
+                // Ownership may already be lost during shutdown.
+            }
+        }
+
+        _mutex.Dispose();
+    }
+
+    private async Task ListenForActivationAsync(Action onActivationRequested, CancellationToken cancellationToken)
+    {
+        while (!cancellationToken.IsCancellationRequested)
+        {
+            try
+            {
+                using var server = new NamedPipeServerStream(
+                    _pipeName,
+                    PipeDirection.In,
+                    1,
+                    PipeTransmissionMode.Byte,
+                    PipeOptions.Asynchronous);
+
+                await server.WaitForConnectionAsync(cancellationToken).ConfigureAwait(false);
+                await server.ReadAsync(new byte[1], cancellationToken).ConfigureAwait(false);
+                onActivationRequested();
+            }
+            catch (OperationCanceledException)
+            {
+                break;
+            }
+            catch (Exception ex)
+            {
+                AppLogger.Warn("SingleInstance", "Activation listener failed.", ex);
+                await Task.Delay(TimeSpan.FromMilliseconds(250), cancellationToken).ConfigureAwait(false);
+            }
+        }
+    }
+}

LanMountainDesktop/Services/StudyAnalyticsService.cs

@@ -16,6 +16,14 @@ public static class StudyAnalyticsServiceFactory
     {
         return SharedService.Value;
     }
+
+    public static void DisposeSharedService()
+    {
+        if (SharedService.IsValueCreated)
+        {
+            SharedService.Value.Dispose();
+        }
+    }
 }
 
 public sealed class StudyAnalyticsService : IStudyAnalyticsService
@@ -446,6 +454,7 @@ public sealed class StudyAnalyticsService : IStudyAnalyticsService
             _disposed = true;
             StopTimerLocked();
             _samplingTimer.Dispose();
+            _audioRecorderService.Dispose();
         }
     }
 
@@ -759,4 +768,3 @@ public sealed class StudyAnalyticsService : IStudyAnalyticsService
         _lastSessionReport = null;
     }
 }
-

LanMountainDesktop/Services/WindowsNativeDialogService.cs

@@ -6,9 +6,20 @@ namespace LanMountainDesktop.Services;
 internal static class WindowsNativeDialogService
 {
     private const uint Ok = 0x00000000;
+    private const uint IconInformation = 0x00000040;
     private const uint IconWarning = 0x00000030;
 
+    public static void ShowInformation(string caption, string message)
+    {
+        Show(caption, message, Ok | IconInformation, "NativeDialog");
+    }
+
     public static void ShowWarning(string caption, string message)
+    {
+        Show(caption, message, Ok | IconWarning, "StartupDiagnostics");
+    }
+
+    private static void Show(string caption, string message, uint type, string logCategory)
     {
         if (!OperatingSystem.IsWindows())
         {
@@ -17,11 +28,11 @@ internal static class WindowsNativeDialogService
 
         try
         {
-            _ = MessageBoxW(IntPtr.Zero, message, caption, Ok | IconWarning);
+            _ = MessageBoxW(IntPtr.Zero, message, caption, type);
         }
         catch (Exception ex)
         {
-            AppLogger.Warn("StartupDiagnostics", "Failed to show legacy executable warning dialog.", ex);
+            AppLogger.Warn(logCategory, "Failed to show native dialog.", ex);
         }
     }
 

LanMountainDesktop/Views/MainWindow.DesktopPaging.cs

@@ -1195,11 +1195,22 @@ public partial class MainWindow
 
         var restoreButton = new Button
         {
-            Content = L("settings.launcher.restore_button", "Unhide"),
-            MinWidth = 110,
-            Padding = new Thickness(12, 6),
+            Width = 36,
+            Height = 36,
+            Padding = new Thickness(0),
+            Background = Brushes.Transparent,
+            BorderThickness = new Thickness(0),
             Tag = new LauncherHiddenItemToken(hiddenItem.Kind, hiddenItem.Key)
         };
+        restoreButton.Content = new FluentIcons.Avalonia.Fluent.SymbolIcon
+        {
+            Symbol = FluentIcons.Common.Symbol.Eye,
+            IconVariant = FluentIcons.Common.IconVariant.Regular,
+            FontSize = 18,
+            HorizontalAlignment = HorizontalAlignment.Center,
+            VerticalAlignment = VerticalAlignment.Center
+        };
+        ToolTip.SetTip(restoreButton, L("settings.launcher.restore_button", "Unhide"));
         restoreButton.Click += OnRestoreLauncherHiddenItemClick;
 
         return new SettingsExpanderItem

LanMountainDesktop/Views/MainWindow.RestartPrompt.cs

@@ -2,6 +2,7 @@ using System.Threading.Tasks;
 using Avalonia.Interactivity;
 using Avalonia.Threading;
 using FluentAvalonia.UI.Controls;
+using LanMountainDesktop.PluginSdk;
 using LanMountainDesktop.Services;
 
 namespace LanMountainDesktop.Views;
@@ -77,7 +78,9 @@ public partial class MainWindow
             var result = await dialog.ShowAsync(this);
             if (result == ContentDialogResult.Primary)
             {
-                if (!AppRestartService.TryRestartApplication())
+                if (App.CurrentHostApplicationLifecycle?.TryRestart(new HostApplicationLifecycleRequest(
+                        Source: nameof(MainWindow),
+                        Reason: "User confirmed a pending restart prompt.")) != true)
                 {
                     UpdatePendingRestartDock();
                 }

LanMountainDesktop/Views/MainWindow.Settings.cs

@@ -158,6 +158,7 @@ public partial class MainWindow
         }
 
         ApplyTaskbarActionVisibility(GetCurrentTaskbarContext());
+        UpdateVideoWallpaperPreviewVisibility();
     }
 
     private void OnNightModeChecked(object? sender, RoutedEventArgs e)
@@ -344,6 +345,7 @@ public partial class MainWindow
         var placement = GetSelectedWallpaperPlacement();
         DesktopWallpaperLayer.Background = CreateWallpaperBrush(_wallpaperBitmap, placement, false);
         WallpaperPreviewViewport.Background = CreateWallpaperBrush(_wallpaperBitmap, placement, true);
+        UpdateVideoWallpaperPreviewVisibility();
     }
 
     private void UpdateWallpaperDisplay()
@@ -628,12 +630,99 @@ public partial class MainWindow
                 EnableHardwareDecoding = false
             };
         }
+    }
 
-        if (_previewVideoWallpaperPlayer is null && WallpaperPreviewVideoView is not null)
+    private void EnsureDesktopVideoFrameRefreshTimer()
+    {
+        if (_desktopVideoFrameRefreshTimer is not null)
         {
-            _previewVideoWallpaperPlayer = new MediaPlayer(_libVlc);
-            WallpaperPreviewVideoView.MediaPlayer = _previewVideoWallpaperPlayer;
+            return;
         }
+
+        _desktopVideoFrameRefreshTimer = new DispatcherTimer
+        {
+            Interval = TimeSpan.FromMilliseconds(33)
+        };
+        _desktopVideoFrameRefreshTimer.Tick += OnDesktopVideoFrameRefreshTimerTick;
+    }
+
+    private void StartDesktopVideoFrameRefreshTimer()
+    {
+        EnsureDesktopVideoFrameRefreshTimer();
+        if (_desktopVideoFrameRefreshTimer?.IsEnabled == false)
+        {
+            _desktopVideoFrameRefreshTimer.Start();
+        }
+    }
+
+    private void StopDesktopVideoFrameRefreshTimer()
+    {
+        if (_desktopVideoFrameRefreshTimer?.IsEnabled == true)
+        {
+            _desktopVideoFrameRefreshTimer.Stop();
+        }
+    }
+
+    private void OnDesktopVideoFrameRefreshTimerTick(object? sender, EventArgs e)
+    {
+        PushDesktopVideoFrameToWallpaperImage();
+    }
+
+    private void UpdateVideoWallpaperPreviewVisibility()
+    {
+        var shouldShowPreview =
+            _wallpaperMediaType == WallpaperMediaType.Video &&
+            _isSettingsOpen &&
+            SettingsPage.IsVisible &&
+            WallpaperSettingsPanel.IsVisible &&
+            _wallpaperPreviewSnapshotBitmap is not null;
+
+        WallpaperPreviewVideoImage.IsVisible = shouldShowPreview;
+        if (shouldShowPreview && !ReferenceEquals(WallpaperPreviewVideoImage.Source, _wallpaperPreviewSnapshotBitmap))
+        {
+            WallpaperPreviewVideoImage.Source = _wallpaperPreviewSnapshotBitmap;
+        }
+    }
+
+    private void InvalidateVideoWallpaperPreviewSnapshot()
+    {
+        _wallpaperPreviewSnapshotPending = true;
+        _wallpaperPreviewSnapshotBitmap?.Dispose();
+        _wallpaperPreviewSnapshotBitmap = null;
+        WallpaperPreviewVideoImage.Source = null;
+    }
+
+    private void CaptureVideoWallpaperPreviewSnapshotFromStagingBuffer()
+    {
+        if (!_wallpaperPreviewSnapshotPending ||
+            _desktopVideoStagingBuffer is null ||
+            _desktopVideoFrameWidth <= 0 ||
+            _desktopVideoFrameHeight <= 0 ||
+            _desktopVideoFramePitch <= 0)
+        {
+            return;
+        }
+
+        _wallpaperPreviewSnapshotBitmap?.Dispose();
+        _wallpaperPreviewSnapshotBitmap = new WriteableBitmap(
+            new PixelSize(_desktopVideoFrameWidth, _desktopVideoFrameHeight),
+            new Vector(96, 96),
+            PixelFormat.Bgra8888,
+            AlphaFormat.Opaque);
+
+        using var framebuffer = _wallpaperPreviewSnapshotBitmap.Lock();
+        var rows = Math.Min(framebuffer.Size.Height, _desktopVideoFrameHeight);
+        var bytesPerRow = Math.Min(framebuffer.RowBytes, _desktopVideoFramePitch);
+        for (var row = 0; row < rows; row++)
+        {
+            var sourceOffset = row * _desktopVideoFramePitch;
+            var destinationPtr = IntPtr.Add(framebuffer.Address, row * framebuffer.RowBytes);
+            Marshal.Copy(_desktopVideoStagingBuffer, sourceOffset, destinationPtr, bytesPerRow);
+        }
+
+        _wallpaperPreviewSnapshotPending = false;
+        WallpaperPreviewVideoImage.Source = _wallpaperPreviewSnapshotBitmap;
+        UpdateVideoWallpaperPreviewVisibility();
     }
 
     private bool ConfigureDesktopVideoRenderer()
@@ -685,6 +774,7 @@ public partial class MainWindow
                 (uint)_desktopVideoFrameHeight,
                 (uint)_desktopVideoFramePitch);
             DesktopVideoWallpaperImage.Source = _desktopVideoBitmap;
+            InvalidateVideoWallpaperPreviewSnapshot();
             return true;
         }
         catch
@@ -745,31 +835,6 @@ public partial class MainWindow
     private void OnDesktopVideoFrameDisplay(IntPtr opaque, IntPtr picture)
     {
         Interlocked.Exchange(ref _desktopVideoFrameDirtyFlag, 1);
-        ScheduleDesktopVideoFrameUiRefresh();
-    }
-
-    private void ScheduleDesktopVideoFrameUiRefresh()
-    {
-        if (Interlocked.Exchange(ref _desktopVideoFrameUiRefreshScheduledFlag, 1) == 1)
-        {
-            return;
-        }
-
-        Dispatcher.UIThread.Post(() =>
-        {
-            try
-            {
-                PushDesktopVideoFrameToWallpaperImage();
-            }
-            finally
-            {
-                Interlocked.Exchange(ref _desktopVideoFrameUiRefreshScheduledFlag, 0);
-                if (Volatile.Read(ref _desktopVideoFrameDirtyFlag) == 1)
-                {
-                    ScheduleDesktopVideoFrameUiRefresh();
-                }
-            }
-        }, DispatcherPriority.Render);
     }
 
     private void PushDesktopVideoFrameToWallpaperImage()
@@ -812,18 +877,22 @@ public partial class MainWindow
         {
             DesktopVideoWallpaperImage.Source = _desktopVideoBitmap;
         }
+
+        CaptureVideoWallpaperPreviewSnapshotFromStagingBuffer();
     }
 
     private void ReleaseDesktopVideoRendererResources()
     {
         Interlocked.Exchange(ref _desktopVideoFrameDirtyFlag, 0);
-        Interlocked.Exchange(ref _desktopVideoFrameUiRefreshScheduledFlag, 0);
 
         if (DesktopVideoWallpaperImage is not null)
         {
             DesktopVideoWallpaperImage.Source = null;
         }
 
+        InvalidateVideoWallpaperPreviewSnapshot();
+        WallpaperPreviewVideoImage.Source = null;
+
         _desktopVideoBitmap?.Dispose();
         _desktopVideoBitmap = null;
         _desktopVideoStagingBuffer = null;
@@ -855,10 +924,8 @@ public partial class MainWindow
         {
             EnsureVideoWallpaperPlayers();
             if (_videoWallpaperPlayer is null ||
-                _previewVideoWallpaperPlayer is null ||
                 _libVlc is null ||
-                DesktopVideoWallpaperImage is null ||
-                WallpaperPreviewVideoView is null)
+                DesktopVideoWallpaperImage is null)
             {
                 _wallpaperStatus = L("settings.wallpaper.video_player_unavailable", "Video player is unavailable.");
                 StopVideoWallpaper();
@@ -873,15 +940,13 @@ public partial class MainWindow
             }
 
             _videoWallpaperMedia?.Dispose();
-            _previewVideoWallpaperMedia?.Dispose();
             _videoWallpaperMedia = new Media(_libVlc, new Uri(videoPath));
-            _previewVideoWallpaperMedia = new Media(_libVlc, new Uri(videoPath));
             _videoWallpaperMedia.AddOption(":input-repeat=65535");
-            _previewVideoWallpaperMedia.AddOption(":input-repeat=65535");
+            InvalidateVideoWallpaperPreviewSnapshot();
             _videoWallpaperPlayer.Play(_videoWallpaperMedia);
-            _previewVideoWallpaperPlayer.Play(_previewVideoWallpaperMedia);
+            StartDesktopVideoFrameRefreshTimer();
             DesktopVideoWallpaperImage.IsVisible = true;
-            WallpaperPreviewVideoView.IsVisible = true;
+            UpdateVideoWallpaperPreviewVisibility();
         }
         catch (Exception ex)
         {
@@ -897,26 +962,17 @@ public partial class MainWindow
             DesktopVideoWallpaperImage.IsVisible = false;
         }
 
-        if (WallpaperPreviewVideoView is not null)
-        {
-            WallpaperPreviewVideoView.IsVisible = false;
-        }
+        WallpaperPreviewVideoImage.IsVisible = false;
 
         if (_videoWallpaperPlayer is not null)
         {
             _videoWallpaperPlayer.Stop();
         }
 
-        if (_previewVideoWallpaperPlayer is not null)
-        {
-            _previewVideoWallpaperPlayer.Stop();
-        }
-
+        StopDesktopVideoFrameRefreshTimer();
         ReleaseDesktopVideoRendererResources();
         _videoWallpaperMedia?.Dispose();
         _videoWallpaperMedia = null;
-        _previewVideoWallpaperMedia?.Dispose();
-        _previewVideoWallpaperMedia = null;
     }
 
     private void PersistSettings()
@@ -2379,7 +2435,14 @@ public partial class MainWindow
         _isSettingsOpen = true;
         UpdateDesktopPageAwareComponentContext();
         UpdateAdaptiveTextSystem();
-        ApplyWallpaperBrush();
+        if (_wallpaperMediaType == WallpaperMediaType.Video)
+        {
+            UpdateVideoWallpaperPreviewVisibility();
+        }
+        else
+        {
+            ApplyWallpaperBrush();
+        }
         ApplyTaskbarActionVisibility(GetCurrentTaskbarContext());
         if (_settingsContentPanelTransform is not null)
         {
@@ -2387,6 +2450,7 @@ public partial class MainWindow
         }
         SettingsPage.IsVisible = true;
         SettingsPage.Opacity = 0;
+        UpdateVideoWallpaperPreviewVisibility();
         UpdateSettingsViewportInsets(Math.Max(1, _currentDesktopCellSize));
 
         UpdateWallpaperPreviewLayout();
@@ -2416,7 +2480,11 @@ public partial class MainWindow
         _isSettingsOpen = false;
         UpdateDesktopPageAwareComponentContext();
         UpdateAdaptiveTextSystem();
-        ApplyWallpaperBrush();
+        UpdateVideoWallpaperPreviewVisibility();
+        if (_wallpaperMediaType != WallpaperMediaType.Video)
+        {
+            ApplyWallpaperBrush();
+        }
         ApplyTaskbarActionVisibility(GetCurrentTaskbarContext());
 
         if (immediate)
@@ -2608,7 +2676,7 @@ public partial class MainWindow
     internal Border WallpaperPreviewHost => WallpaperSettingsPanel.FindControl<Border>("WallpaperPreviewHost")!;
     internal Border WallpaperPreviewFrame => WallpaperSettingsPanel.FindControl<Border>("WallpaperPreviewFrame")!;
     internal Border WallpaperPreviewViewport => WallpaperSettingsPanel.FindControl<Border>("WallpaperPreviewViewport")!;
-    internal LibVLCSharp.Avalonia.VideoView? WallpaperPreviewVideoView => WallpaperSettingsPanel.FindControl<LibVLCSharp.Avalonia.VideoView>("WallpaperPreviewVideoView");
+    internal Image WallpaperPreviewVideoImage => WallpaperSettingsPanel.FindControl<Image>("WallpaperPreviewVideoImage")!;
     internal Grid WallpaperPreviewGrid => WallpaperSettingsPanel.FindControl<Grid>("WallpaperPreviewGrid")!;
     internal Border WallpaperPreviewTopStatusBarHost => WallpaperSettingsPanel.FindControl<Border>("WallpaperPreviewTopStatusBarHost")!;
     internal StackPanel WallpaperPreviewTopStatusComponentsPanel => WallpaperSettingsPanel.FindControl<StackPanel>("WallpaperPreviewTopStatusComponentsPanel")!;

LanMountainDesktop/Views/MainWindow.SingleInstanceNotice.cs

@@ -0,0 +1,59 @@
+using System;
+using Avalonia.Interactivity;
+using Avalonia.Threading;
+
+namespace LanMountainDesktop.Views;
+
+public partial class MainWindow
+{
+    private readonly DispatcherTimer _singleInstanceNoticeTimer = new()
+    {
+        Interval = TimeSpan.FromSeconds(6)
+    };
+
+    internal void ShowSingleInstanceNotice()
+    {
+        if (Dispatcher.UIThread.CheckAccess())
+        {
+            ShowSingleInstanceNoticeCore();
+            return;
+        }
+
+        Dispatcher.UIThread.Post(ShowSingleInstanceNoticeCore, DispatcherPriority.Send);
+    }
+
+    private void ShowSingleInstanceNoticeCore()
+    {
+        SingleInstanceNoticeTitleTextBlock.Text = L(
+            "single_instance.notice.title",
+            "App already open");
+        SingleInstanceNoticeDescriptionTextBlock.Text = L(
+            "single_instance.notice.description",
+            "LanMountainDesktop is already running. Switched back to the active desktop.");
+        SingleInstanceNoticeButtonTextBlock.Text = L(
+            "single_instance.notice.button",
+            "Got it");
+        SingleInstanceNoticeDock.IsVisible = true;
+
+        _singleInstanceNoticeTimer.Stop();
+        _singleInstanceNoticeTimer.Tick -= OnSingleInstanceNoticeTimerTick;
+        _singleInstanceNoticeTimer.Tick += OnSingleInstanceNoticeTimerTick;
+        _singleInstanceNoticeTimer.Start();
+    }
+
+    private void OnSingleInstanceNoticeButtonClick(object? sender, RoutedEventArgs e)
+    {
+        HideSingleInstanceNotice();
+    }
+
+    private void OnSingleInstanceNoticeTimerTick(object? sender, EventArgs e)
+    {
+        HideSingleInstanceNotice();
+    }
+
+    private void HideSingleInstanceNotice()
+    {
+        _singleInstanceNoticeTimer.Stop();
+        SingleInstanceNoticeDock.IsVisible = false;
+    }
+}

LanMountainDesktop/Views/MainWindow.Update.cs

@@ -1,11 +1,12 @@
 using System;
+using System.ComponentModel;
 using System.Diagnostics;
 using System.IO;
 using System.Threading.Tasks;
 using Avalonia.Controls;
 using Avalonia.Interactivity;
-using Avalonia.Threading;
 using LanMountainDesktop.Models;
+using LanMountainDesktop.PluginSdk;
 using LanMountainDesktop.Services;
 
 namespace LanMountainDesktop.Views;
@@ -357,7 +358,8 @@ public partial class MainWindow
             {
                 FileName = installerPath,
                 WorkingDirectory = Path.GetDirectoryName(installerPath) ?? Environment.CurrentDirectory,
-                UseShellExecute = true
+                UseShellExecute = true,
+                Verb = "runas"
             });
 
             _updateStatusText = L(
@@ -365,7 +367,16 @@ public partial class MainWindow
                 "Installer started. The app will close for update.");
             UpdateUpdatePanelState();
 
-            Dispatcher.UIThread.Post(Close, DispatcherPriority.Background);
+            _ = App.CurrentHostApplicationLifecycle?.TryExit(new HostApplicationLifecycleRequest(
+                Source: nameof(MainWindow),
+                Reason: "Update installer started successfully."));
+        }
+        catch (Win32Exception ex) when (ex.NativeErrorCode == 1223)
+        {
+            _updateStatusText = L(
+                "settings.update.status_elevation_cancelled",
+                "Administrator permission was not granted. Update was cancelled.");
+            UpdateUpdatePanelState();
         }
         catch (Exception ex)
         {

LanMountainDesktop/Views/MainWindow.axaml

@@ -469,51 +469,98 @@
                             </ScrollViewer>
                         </ui:NavigationView>
 
-                        <Border x:Name="PendingRestartDock"
-                                Grid.Row="1"
-                                IsVisible="False"
-                                Classes="glass-panel"
-                                CornerRadius="18"
-                                Padding="14,12">
-                            <Grid ColumnDefinitions="Auto,*,Auto"
-                                  ColumnSpacing="12">
-                                <Border Width="34"
-                                        Height="34"
-                                        CornerRadius="17"
-                                        Background="{DynamicResource AdaptiveAccentBrush}">
-                                    <fi:FluentIcon Icon="ArrowSync"
-                                                   IconVariant="Regular"
-                                                   FontSize="16"
-                                                   Foreground="White"
-                                                   HorizontalAlignment="Center"
-                                                   VerticalAlignment="Center" />
-                                </Border>
-                                <StackPanel Grid.Column="1"
-                                            Spacing="2"
-                                            VerticalAlignment="Center">
-                                    <TextBlock x:Name="PendingRestartDockTitleTextBlock"
-                                               FontSize="13"
-                                               FontWeight="SemiBold"
-                                               Text="Restart required" />
-                                    <TextBlock x:Name="PendingRestartDockDescriptionTextBlock"
-                                               TextWrapping="Wrap"
-                                               Foreground="{DynamicResource AdaptiveTextSecondaryBrush}"
-                                               Text="Your changes will apply after restarting the app." />
-                                </StackPanel>
-                                <Button x:Name="PendingRestartDockButton"
-                                        Grid.Column="2"
-                                        Padding="14,8"
-                                        Click="OnPendingRestartDockButtonClick">
-                                    <StackPanel Orientation="Horizontal" Spacing="8">
-                                        <fi:FluentIcon Icon="ArrowSync"
-                                                       IconVariant="Regular" />
-                                        <TextBlock x:Name="PendingRestartDockButtonTextBlock"
-                                                   VerticalAlignment="Center"
-                                                   Text="Restart app" />
+                        <StackPanel Grid.Row="1"
+                                    Spacing="12">
+                            <Border x:Name="SingleInstanceNoticeDock"
+                                    IsVisible="False"
+                                    Classes="glass-panel"
+                                    CornerRadius="18"
+                                    Padding="14,12">
+                                <Grid ColumnDefinitions="Auto,*,Auto"
+                                      ColumnSpacing="12">
+                                    <Border Width="34"
+                                            Height="34"
+                                            CornerRadius="17"
+                                            Background="{DynamicResource AdaptiveAccentBrush}">
+                                        <fi:FluentIcon Icon="Alert"
+                                                       IconVariant="Regular"
+                                                       FontSize="16"
+                                                       Foreground="White"
+                                                       HorizontalAlignment="Center"
+                                                       VerticalAlignment="Center" />
+                                    </Border>
+                                    <StackPanel Grid.Column="1"
+                                                Spacing="2"
+                                                VerticalAlignment="Center">
+                                        <TextBlock x:Name="SingleInstanceNoticeTitleTextBlock"
+                                                   FontSize="13"
+                                                   FontWeight="SemiBold"
+                                                   Text="App already open" />
+                                        <TextBlock x:Name="SingleInstanceNoticeDescriptionTextBlock"
+                                                   TextWrapping="Wrap"
+                                                   Foreground="{DynamicResource AdaptiveTextSecondaryBrush}"
+                                                   Text="LanMountainDesktop is already running. Switched back to the active desktop." />
                                     </StackPanel>
-                                </Button>
-                            </Grid>
-                        </Border>
+                                    <Button x:Name="SingleInstanceNoticeButton"
+                                            Grid.Column="2"
+                                            Padding="14,8"
+                                            Click="OnSingleInstanceNoticeButtonClick">
+                                        <StackPanel Orientation="Horizontal" Spacing="8">
+                                            <fi:FluentIcon Icon="Checkmark"
+                                                           IconVariant="Regular" />
+                                            <TextBlock x:Name="SingleInstanceNoticeButtonTextBlock"
+                                                       VerticalAlignment="Center"
+                                                       Text="Got it" />
+                                        </StackPanel>
+                                    </Button>
+                                </Grid>
+                            </Border>
+
+                            <Border x:Name="PendingRestartDock"
+                                    IsVisible="False"
+                                    Classes="glass-panel"
+                                    CornerRadius="18"
+                                    Padding="14,12">
+                                <Grid ColumnDefinitions="Auto,*,Auto"
+                                      ColumnSpacing="12">
+                                    <Border Width="34"
+                                            Height="34"
+                                            CornerRadius="17"
+                                            Background="{DynamicResource AdaptiveAccentBrush}">
+                                        <fi:FluentIcon Icon="ArrowSync"
+                                                       IconVariant="Regular"
+                                                       FontSize="16"
+                                                       Foreground="White"
+                                                       HorizontalAlignment="Center"
+                                                       VerticalAlignment="Center" />
+                                    </Border>
+                                    <StackPanel Grid.Column="1"
+                                                Spacing="2"
+                                                VerticalAlignment="Center">
+                                        <TextBlock x:Name="PendingRestartDockTitleTextBlock"
+                                                   FontSize="13"
+                                                   FontWeight="SemiBold"
+                                                   Text="Restart required" />
+                                        <TextBlock x:Name="PendingRestartDockDescriptionTextBlock"
+                                                   TextWrapping="Wrap"
+                                                   Foreground="{DynamicResource AdaptiveTextSecondaryBrush}"
+                                                   Text="Your changes will apply after restarting the app." />
+                                    </StackPanel>
+                                    <Button x:Name="PendingRestartDockButton"
+                                            Grid.Column="2"
+                                            Padding="14,8"
+                                            Click="OnPendingRestartDockButtonClick">
+                                        <StackPanel Orientation="Horizontal" Spacing="8">
+                                            <fi:FluentIcon Icon="ArrowSync"
+                                                           IconVariant="Regular" />
+                                            <TextBlock x:Name="PendingRestartDockButtonTextBlock"
+                                                       VerticalAlignment="Center"
+                                                       Text="Restart app" />
+                                        </StackPanel>
+                                    </Button>
+                                </Grid>
+                            </Border>
+                        </StackPanel>
                     </Grid>
                 </Border>
             </Border>

LanMountainDesktop/Views/MainWindow.axaml.cs

@@ -124,21 +124,21 @@ public partial class MainWindow : Window
     private LibVLC? _libVlc;
     private MediaPlayer? _videoWallpaperPlayer;
     private Media? _videoWallpaperMedia;
-    private MediaPlayer? _previewVideoWallpaperPlayer;
-    private Media? _previewVideoWallpaperMedia;
     private readonly object _desktopVideoFrameSync = new();
     private MediaPlayer.LibVLCVideoLockCb? _desktopVideoLockCallback;
     private MediaPlayer.LibVLCVideoUnlockCb? _desktopVideoUnlockCallback;
     private MediaPlayer.LibVLCVideoDisplayCb? _desktopVideoDisplayCallback;
+    private DispatcherTimer? _desktopVideoFrameRefreshTimer;
     private IntPtr _desktopVideoFrameBufferPtr;
     private byte[]? _desktopVideoStagingBuffer;
     private WriteableBitmap? _desktopVideoBitmap;
+    private WriteableBitmap? _wallpaperPreviewSnapshotBitmap;
     private int _desktopVideoFrameWidth;
     private int _desktopVideoFrameHeight;
     private int _desktopVideoFramePitch;
     private int _desktopVideoFrameBufferSize;
     private int _desktopVideoFrameDirtyFlag;
-    private int _desktopVideoFrameUiRefreshScheduledFlag;
+    private bool _wallpaperPreviewSnapshotPending;
     private string? _wallpaperPath;
     private string _wallpaperStatus = "Current background uses solid color.";
     private IReadOnlyList<Color> _recommendedColors = Array.Empty<Color>();
@@ -384,15 +384,15 @@ public partial class MainWindow : Window
     {
         PersistSettings();
         StopVideoWallpaper();
-        _previewVideoWallpaperMedia?.Dispose();
-        _previewVideoWallpaperMedia = null;
-        _previewVideoWallpaperPlayer?.Dispose();
-        _previewVideoWallpaperPlayer = null;
         DisposeLauncherResources();
         _videoWallpaperMedia?.Dispose();
         _videoWallpaperMedia = null;
         _videoWallpaperPlayer?.Dispose();
         _videoWallpaperPlayer = null;
+        _desktopVideoFrameRefreshTimer?.Stop();
+        _desktopVideoFrameRefreshTimer = null;
+        _wallpaperPreviewSnapshotBitmap?.Dispose();
+        _wallpaperPreviewSnapshotBitmap = null;
         _libVlc?.Dispose();
         _libVlc = null;
         if (_weatherDataService is IDisposable weatherServiceDisposable)

LanMountainDesktop/Views/SettingsPages/WallpaperSettingsPage.axaml

@@ -6,7 +6,6 @@
              xmlns:fi="using:FluentIcons.Avalonia"
              xmlns:ic="using:FluentIcons.Avalonia.Fluent"
              xmlns:comp="using:LanMountainDesktop.Views.Components"
-             xmlns:vlc="clr-namespace:LibVLCSharp.Avalonia;assembly=LibVLCSharp.Avalonia"
              mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="600"
              x:Class="LanMountainDesktop.Views.SettingsPages.WallpaperSettingsPage">
     <Grid x:Name="WallpaperSettingsPanel"
@@ -37,11 +36,12 @@
                         CornerRadius="12"
                         Background="#30111827">
                     <Grid>
-                        <vlc:VideoView x:Name="WallpaperPreviewVideoView"
-                                       IsVisible="False"
-                                       IsHitTestVisible="False"
-                                       HorizontalAlignment="Stretch"
-                                       VerticalAlignment="Stretch" />
+                        <Image x:Name="WallpaperPreviewVideoImage"
+                               IsVisible="False"
+                               IsHitTestVisible="False"
+                               Stretch="UniformToFill"
+                               HorizontalAlignment="Stretch"
+                               VerticalAlignment="Stretch" />
 
                         <Grid x:Name="WallpaperPreviewGrid"
                               HorizontalAlignment="Center"

LanMountainDesktop/Views/SettingsWindow.Controls.cs

@@ -1,7 +1,6 @@
 using Avalonia.Controls;
 using Avalonia.Media;
 using Avalonia.Media.Imaging;
-using LibVLCSharp.Avalonia;
 namespace LanMountainDesktop.Views;
 
 public partial class SettingsWindow
@@ -14,7 +13,7 @@ public partial class SettingsWindow
     internal Border WallpaperPreviewHost => WallpaperSettingsPanel.FindControl<Border>("WallpaperPreviewHost")!;
     internal Border WallpaperPreviewFrame => WallpaperSettingsPanel.FindControl<Border>("WallpaperPreviewFrame")!;
     internal Border WallpaperPreviewViewport => WallpaperSettingsPanel.FindControl<Border>("WallpaperPreviewViewport")!;
-    internal LibVLCSharp.Avalonia.VideoView? WallpaperPreviewVideoView => WallpaperSettingsPanel.FindControl<LibVLCSharp.Avalonia.VideoView>("WallpaperPreviewVideoView");
+    internal Image WallpaperPreviewVideoImage => WallpaperSettingsPanel.FindControl<Image>("WallpaperPreviewVideoImage")!;
     internal Grid WallpaperPreviewGrid => WallpaperSettingsPanel.FindControl<Grid>("WallpaperPreviewGrid")!;
     internal Border WallpaperPreviewTopStatusBarHost => WallpaperSettingsPanel.FindControl<Border>("WallpaperPreviewTopStatusBarHost")!;
     internal StackPanel WallpaperPreviewTopStatusComponentsPanel => WallpaperSettingsPanel.FindControl<StackPanel>("WallpaperPreviewTopStatusComponentsPanel")!;

LanMountainDesktop/Views/SettingsWindow.Core.cs

@@ -29,6 +29,8 @@ public partial class SettingsWindow
         _previewVideoWallpaperPlayer = null;
         _previewVideoWallpaperMedia?.Dispose();
         _previewVideoWallpaperMedia = null;
+        _previewVideoFrameRefreshTimer?.Stop();
+        _previewVideoFrameRefreshTimer = null;
         _libVlc?.Dispose();
         _libVlc = null;
 
@@ -254,6 +256,7 @@ public partial class SettingsWindow
         }
 
         ApplyTaskbarActionVisibility(GetCurrentTaskbarContext());
+        SyncVideoWallpaperPreviewPlayback();
     }
 
     private void PersistSettings()

LanMountainDesktop/Views/SettingsWindow.RestartPrompt.cs

@@ -2,6 +2,7 @@ using System.Threading.Tasks;
 using Avalonia.Interactivity;
 using Avalonia.Threading;
 using FluentAvalonia.UI.Controls;
+using LanMountainDesktop.PluginSdk;
 using LanMountainDesktop.Services;
 
 namespace LanMountainDesktop.Views;
@@ -77,7 +78,9 @@ public partial class SettingsWindow
             var result = await dialog.ShowAsync(this);
             if (result == ContentDialogResult.Primary)
             {
-                if (!AppRestartService.TryRestartApplication())
+                if (App.CurrentHostApplicationLifecycle?.TryRestart(new HostApplicationLifecycleRequest(
+                        Source: nameof(SettingsWindow),
+                        Reason: "User confirmed a pending restart prompt from settings.")) != true)
                 {
                     UpdatePendingRestartDock();
                 }

LanMountainDesktop/Views/SettingsWindow.Update.cs

@@ -1,13 +1,12 @@
 using System;
+using System.ComponentModel;
 using System.Diagnostics;
 using System.IO;
 using System.Threading.Tasks;
-using Avalonia;
 using Avalonia.Controls;
-using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Interactivity;
-using Avalonia.Threading;
 using LanMountainDesktop.Models;
+using LanMountainDesktop.PluginSdk;
 using LanMountainDesktop.Services;
 
 namespace LanMountainDesktop.Views;
@@ -250,23 +249,23 @@ public partial class SettingsWindow
             {
                 FileName = installerPath,
                 WorkingDirectory = Path.GetDirectoryName(installerPath) ?? Environment.CurrentDirectory,
-                UseShellExecute = true
+                UseShellExecute = true,
+                Verb = "runas"
             });
 
             _updateStatusText = L("settings.update.status_installer_started", "Installer started. The app will close for update.");
             UpdateUpdatePanelState();
 
-            Dispatcher.UIThread.Post(() =>
-            {
-                if (Application.Current?.ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
-                {
-                    desktop.Shutdown();
-                }
-                else
-                {
-                    Close();
-                }
-            }, DispatcherPriority.Background);
+            _ = App.CurrentHostApplicationLifecycle?.TryExit(new HostApplicationLifecycleRequest(
+                Source: nameof(SettingsWindow),
+                Reason: "Update installer started successfully from settings."));
+        }
+        catch (Win32Exception ex) when (ex.NativeErrorCode == 1223)
+        {
+            _updateStatusText = L(
+                "settings.update.status_elevation_cancelled",
+                "Administrator permission was not granted. Update was cancelled.");
+            UpdateUpdatePanelState();
         }
         catch (Exception ex)
         {

LanMountainDesktop/Views/SettingsWindow.WallpaperTheme.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Globalization;
 using System.IO;
 using System.Runtime.InteropServices;
+using System.Threading;
 using System.Threading.Tasks;
 using Avalonia;
 using Avalonia.Controls;
@@ -12,6 +13,7 @@ using Avalonia.Media.Imaging;
 using Avalonia.Platform;
 using Avalonia.Styling;
 using Avalonia.Platform.Storage;
+using Avalonia.Threading;
 using LanMountainDesktop.Services;
 using LanMountainDesktop.Theme;
 using LibVLCSharp.Shared;
@@ -157,7 +159,7 @@ public partial class SettingsWindow
         {
             DesktopWallpaperLayer.Background = Brushes.Transparent;
             WallpaperPreviewViewport.Background = GetThemeDefaultDesktopBackground();
-            PlayVideoWallpaper(_wallpaperVideoPath);
+            SyncVideoWallpaperPreviewPlayback();
             return;
         }
 
@@ -175,6 +177,36 @@ public partial class SettingsWindow
         WallpaperPreviewViewport.Background = CreateWallpaperBrush(_wallpaperBitmap, placement, true);
     }
 
+    private void SyncVideoWallpaperPreviewPlayback()
+    {
+        var shouldPlay =
+            _wallpaperMediaType == WallpaperMediaType.Video &&
+            !string.IsNullOrWhiteSpace(_wallpaperVideoPath) &&
+            WallpaperSettingsPanel.IsVisible;
+
+        if (!shouldPlay)
+        {
+            if (_previewVideoWallpaperPlayer?.IsPlaying == true)
+            {
+                StopPreviewVideoCapture(clearSnapshot: false);
+            }
+
+            WallpaperPreviewVideoImage.IsVisible = WallpaperPreviewVideoImage.Source is not null && WallpaperSettingsPanel.IsVisible;
+            return;
+        }
+
+        if (WallpaperPreviewVideoImage.Source is not null)
+        {
+            WallpaperPreviewVideoImage.IsVisible = true;
+            return;
+        }
+
+        if (_previewVideoWallpaperMedia is null || _previewVideoSnapshotPending)
+        {
+            PlayVideoWallpaper(_wallpaperVideoPath!);
+        }
+    }
+
     private void UpdateWallpaperDisplay()
     {
         WallpaperPathTextBlock.Text = string.IsNullOrWhiteSpace(_wallpaperPath)
@@ -417,11 +449,239 @@ public partial class SettingsWindow
     private void EnsureVideoWallpaperPlayers()
     {
         Core.Initialize();
-        _libVlc ??= new LibVLC();
-        _previewVideoWallpaperPlayer ??= new MediaPlayer(_libVlc);
-        if (WallpaperPreviewVideoView is not null)
+        _libVlc ??= new LibVLC("--quiet");
+        if (_previewVideoWallpaperPlayer is null)
         {
-            WallpaperPreviewVideoView.MediaPlayer = _previewVideoWallpaperPlayer;
+            _previewVideoWallpaperPlayer = new MediaPlayer(_libVlc)
+            {
+                EnableHardwareDecoding = false
+            };
+        }
+    }
+
+    private void EnsurePreviewVideoFrameRefreshTimer()
+    {
+        if (_previewVideoFrameRefreshTimer is not null)
+        {
+            return;
+        }
+
+        _previewVideoFrameRefreshTimer = new DispatcherTimer
+        {
+            Interval = TimeSpan.FromMilliseconds(33)
+        };
+        _previewVideoFrameRefreshTimer.Tick += OnPreviewVideoFrameRefreshTimerTick;
+    }
+
+    private void StartPreviewVideoFrameRefreshTimer()
+    {
+        EnsurePreviewVideoFrameRefreshTimer();
+        if (_previewVideoFrameRefreshTimer?.IsEnabled == false)
+        {
+            _previewVideoFrameRefreshTimer.Start();
+        }
+    }
+
+    private void StopPreviewVideoFrameRefreshTimer()
+    {
+        if (_previewVideoFrameRefreshTimer?.IsEnabled == true)
+        {
+            _previewVideoFrameRefreshTimer.Stop();
+        }
+    }
+
+    private void OnPreviewVideoFrameRefreshTimerTick(object? sender, EventArgs e)
+    {
+        PushPreviewVideoFrameToWallpaperImage();
+    }
+
+    private void StopPreviewVideoCapture(bool clearSnapshot)
+    {
+        WallpaperPreviewVideoImage.IsVisible = false;
+        _previewVideoWallpaperPlayer?.Stop();
+        StopPreviewVideoFrameRefreshTimer();
+        _previewVideoWallpaperMedia?.Dispose();
+        _previewVideoWallpaperMedia = null;
+        _previewVideoSnapshotPending = false;
+
+        if (clearSnapshot)
+        {
+            ReleasePreviewVideoRendererResources();
+        }
+    }
+
+    private bool ConfigurePreviewVideoRenderer()
+    {
+        if (_previewVideoWallpaperPlayer is null)
+        {
+            return false;
+        }
+
+        var hostWidth = Math.Max(1, WallpaperPreviewViewport.Bounds.Width);
+        var hostHeight = Math.Max(1, WallpaperPreviewViewport.Bounds.Height);
+        var pixelWidth = Math.Max(1, (int)Math.Round(hostWidth * RenderScaling));
+        var pixelHeight = Math.Max(1, (int)Math.Round(hostHeight * RenderScaling));
+        const int maxPixelCount = 1280 * 720;
+        var pixelCount = (long)pixelWidth * pixelHeight;
+        if (pixelCount > maxPixelCount)
+        {
+            var scale = Math.Sqrt((double)maxPixelCount / pixelCount);
+            pixelWidth = Math.Max(1, (int)Math.Round(pixelWidth * scale));
+            pixelHeight = Math.Max(1, (int)Math.Round(pixelHeight * scale));
+        }
+
+        var pitch = pixelWidth * 4;
+        var bufferSize = pitch * pixelHeight;
+        if (bufferSize <= 0)
+        {
+            return false;
+        }
+
+        if (pixelWidth == _previewVideoFrameWidth &&
+            pixelHeight == _previewVideoFrameHeight &&
+            _previewVideoFrameBufferPtr != IntPtr.Zero &&
+            _previewVideoBitmap is not null)
+        {
+            return true;
+        }
+
+        ReleasePreviewVideoRendererResources();
+
+        try
+        {
+            _previewVideoFrameWidth = pixelWidth;
+            _previewVideoFrameHeight = pixelHeight;
+            _previewVideoFramePitch = pitch;
+            _previewVideoFrameBufferSize = bufferSize;
+            _previewVideoFrameBufferPtr = Marshal.AllocHGlobal(_previewVideoFrameBufferSize);
+            _previewVideoStagingBuffer = new byte[_previewVideoFrameBufferSize];
+            _previewVideoBitmap = new WriteableBitmap(
+                new PixelSize(_previewVideoFrameWidth, _previewVideoFrameHeight),
+                new Vector(96, 96),
+                PixelFormat.Bgra8888,
+                AlphaFormat.Opaque);
+            EnsurePreviewVideoCallbacks();
+            _previewVideoWallpaperPlayer.SetVideoCallbacks(
+                _previewVideoLockCallback!,
+                _previewVideoUnlockCallback!,
+                _previewVideoDisplayCallback!);
+            _previewVideoWallpaperPlayer.SetVideoFormat(
+                "RV32",
+                (uint)_previewVideoFrameWidth,
+                (uint)_previewVideoFrameHeight,
+                (uint)_previewVideoFramePitch);
+            WallpaperPreviewVideoImage.Source = _previewVideoBitmap;
+            return true;
+        }
+        catch
+        {
+            ReleasePreviewVideoRendererResources();
+            return false;
+        }
+    }
+
+    private void EnsurePreviewVideoCallbacks()
+    {
+        _previewVideoLockCallback ??= OnPreviewVideoFrameLock;
+        _previewVideoUnlockCallback ??= OnPreviewVideoFrameUnlock;
+        _previewVideoDisplayCallback ??= OnPreviewVideoFrameDisplay;
+    }
+
+    private IntPtr OnPreviewVideoFrameLock(IntPtr opaque, IntPtr planes)
+    {
+        Monitor.Enter(_previewVideoFrameSync);
+        if (_previewVideoFrameBufferPtr == IntPtr.Zero)
+        {
+            Marshal.WriteIntPtr(planes, IntPtr.Zero);
+            Monitor.Exit(_previewVideoFrameSync);
+            return IntPtr.Zero;
+        }
+
+        Marshal.WriteIntPtr(planes, _previewVideoFrameBufferPtr);
+        return IntPtr.Zero;
+    }
+
+    private void OnPreviewVideoFrameUnlock(IntPtr opaque, IntPtr picture, IntPtr planes)
+    {
+        if (Monitor.IsEntered(_previewVideoFrameSync))
+        {
+            Monitor.Exit(_previewVideoFrameSync);
+        }
+    }
+
+    private void OnPreviewVideoFrameDisplay(IntPtr opaque, IntPtr picture)
+    {
+        Interlocked.Exchange(ref _previewVideoFrameDirtyFlag, 1);
+    }
+
+    private void PushPreviewVideoFrameToWallpaperImage()
+    {
+        if (Interlocked.Exchange(ref _previewVideoFrameDirtyFlag, 0) == 0)
+        {
+            return;
+        }
+
+        if (_previewVideoBitmap is null ||
+            _previewVideoStagingBuffer is null ||
+            _previewVideoFrameBufferPtr == IntPtr.Zero ||
+            _previewVideoFrameBufferSize <= 0)
+        {
+            return;
+        }
+
+        lock (_previewVideoFrameSync)
+        {
+            if (_previewVideoFrameBufferPtr == IntPtr.Zero)
+            {
+                return;
+            }
+
+            Marshal.Copy(_previewVideoFrameBufferPtr, _previewVideoStagingBuffer, 0, _previewVideoFrameBufferSize);
+        }
+
+        using var framebuffer = _previewVideoBitmap.Lock();
+        var rows = Math.Min(framebuffer.Size.Height, _previewVideoFrameHeight);
+        var bytesPerRow = Math.Min(framebuffer.RowBytes, _previewVideoFramePitch);
+        for (var row = 0; row < rows; row++)
+        {
+            var sourceOffset = row * _previewVideoFramePitch;
+            var destinationPtr = IntPtr.Add(framebuffer.Address, row * framebuffer.RowBytes);
+            Marshal.Copy(_previewVideoStagingBuffer, sourceOffset, destinationPtr, bytesPerRow);
+        }
+
+        if (!ReferenceEquals(WallpaperPreviewVideoImage.Source, _previewVideoBitmap))
+        {
+            WallpaperPreviewVideoImage.Source = _previewVideoBitmap;
+        }
+
+        if (_previewVideoSnapshotPending)
+        {
+            _previewVideoSnapshotPending = false;
+            WallpaperPreviewVideoImage.IsVisible = WallpaperSettingsPanel.IsVisible;
+            StopPreviewVideoCapture(clearSnapshot: false);
+            WallpaperPreviewVideoImage.IsVisible = WallpaperSettingsPanel.IsVisible;
+        }
+    }
+
+    private void ReleasePreviewVideoRendererResources()
+    {
+        Interlocked.Exchange(ref _previewVideoFrameDirtyFlag, 0);
+        WallpaperPreviewVideoImage.Source = null;
+        _previewVideoBitmap?.Dispose();
+        _previewVideoBitmap = null;
+        _previewVideoStagingBuffer = null;
+        _previewVideoFrameWidth = 0;
+        _previewVideoFrameHeight = 0;
+        _previewVideoFramePitch = 0;
+        _previewVideoFrameBufferSize = 0;
+
+        lock (_previewVideoFrameSync)
+        {
+            if (_previewVideoFrameBufferPtr != IntPtr.Zero)
+            {
+                Marshal.FreeHGlobal(_previewVideoFrameBufferPtr);
+                _previewVideoFrameBufferPtr = IntPtr.Zero;
+            }
         }
     }
 
@@ -437,7 +697,14 @@ public partial class SettingsWindow
         try
         {
             EnsureVideoWallpaperPlayers();
-            if (_previewVideoWallpaperPlayer is null || _libVlc is null || WallpaperPreviewVideoView is null)
+            if (_previewVideoWallpaperPlayer is null || _libVlc is null)
+            {
+                _wallpaperStatus = L("settings.wallpaper.video_player_unavailable", "Video player is unavailable.");
+                StopVideoWallpaper();
+                return;
+            }
+
+            if (!ConfigurePreviewVideoRenderer())
             {
                 _wallpaperStatus = L("settings.wallpaper.video_player_unavailable", "Video player is unavailable.");
                 StopVideoWallpaper();
@@ -447,8 +714,10 @@ public partial class SettingsWindow
             _previewVideoWallpaperMedia?.Dispose();
             _previewVideoWallpaperMedia = new Media(_libVlc, new Uri(videoPath));
             _previewVideoWallpaperMedia.AddOption(":input-repeat=65535");
+            _previewVideoSnapshotPending = true;
+            WallpaperPreviewVideoImage.IsVisible = false;
             _previewVideoWallpaperPlayer.Play(_previewVideoWallpaperMedia);
-            WallpaperPreviewVideoView.IsVisible = true;
+            StartPreviewVideoFrameRefreshTimer();
         }
         catch (Exception ex)
         {
@@ -459,14 +728,7 @@ public partial class SettingsWindow
 
     private void StopVideoWallpaper()
     {
-        if (WallpaperPreviewVideoView is not null)
-        {
-            WallpaperPreviewVideoView.IsVisible = false;
-        }
-
-        _previewVideoWallpaperPlayer?.Stop();
-        _previewVideoWallpaperMedia?.Dispose();
-        _previewVideoWallpaperMedia = null;
+        StopPreviewVideoCapture(clearSnapshot: true);
     }
 
     private void OnRecommendedColorClick(object? sender, RoutedEventArgs e)

LanMountainDesktop/Views/SettingsWindow.WeatherLauncher.cs

@@ -873,11 +873,22 @@ public partial class SettingsWindow
 
         var restoreButton = new Button
         {
-            Content = L("settings.launcher.restore_button", "Unhide"),
-            MinWidth = 110,
-            Padding = new Thickness(12, 6),
+            Width = 36,
+            Height = 36,
+            Padding = new Thickness(0),
+            Background = Brushes.Transparent,
+            BorderThickness = new Thickness(0),
             Tag = new LauncherHiddenItemToken(hiddenItem.Kind, hiddenItem.Key)
         };
+        restoreButton.Content = new FluentIcons.Avalonia.Fluent.SymbolIcon
+        {
+            Symbol = FluentIcons.Common.Symbol.Eye,
+            IconVariant = FluentIcons.Common.IconVariant.Regular,
+            FontSize = 18,
+            HorizontalAlignment = HorizontalAlignment.Center,
+            VerticalAlignment = VerticalAlignment.Center
+        };
+        ToolTip.SetTip(restoreButton, L("settings.launcher.restore_button", "Unhide"));
         restoreButton.Click += OnRestoreLauncherHiddenItemClick;
 
         return new SettingsExpanderItem

LanMountainDesktop/Views/SettingsWindow.axaml.cs

@@ -129,6 +129,20 @@ public partial class SettingsWindow : Window
     private MediaPlayer? _previewVideoWallpaperPlayer;
     private Media? _previewVideoWallpaperMedia;
     private LibVLC? _libVlc;
+    private readonly object _previewVideoFrameSync = new();
+    private MediaPlayer.LibVLCVideoLockCb? _previewVideoLockCallback;
+    private MediaPlayer.LibVLCVideoUnlockCb? _previewVideoUnlockCallback;
+    private MediaPlayer.LibVLCVideoDisplayCb? _previewVideoDisplayCallback;
+    private DispatcherTimer? _previewVideoFrameRefreshTimer;
+    private IntPtr _previewVideoFrameBufferPtr;
+    private byte[]? _previewVideoStagingBuffer;
+    private WriteableBitmap? _previewVideoBitmap;
+    private int _previewVideoFrameWidth;
+    private int _previewVideoFrameHeight;
+    private int _previewVideoFramePitch;
+    private int _previewVideoFrameBufferSize;
+    private int _previewVideoFrameDirtyFlag;
+    private bool _previewVideoSnapshotPending;
     private string? _wallpaperPath;
     private string _wallpaperStatus = "Current background uses solid color.";
     private IReadOnlyList<Color> _recommendedColors = Array.Empty<Color>();

LanMountainDesktop/installer/LanMountainDesktop.iss

@@ -38,6 +38,8 @@ OutputBaseFilename={#MyAppName}-Setup-{#MyAppVersion}-{#MyAppArch}
 Compression=lzma2/ultra64
 SolidCompression=yes
 WizardStyle=modern
+; Leave PrivilegesRequiredOverridesAllowed unset so users cannot downgrade
+; installation mode via dialog or /ALLUSERS /CURRENTUSER command-line switches.
 PrivilegesRequired=admin
 CloseApplications=yes
 CloseApplicationsFilter={#MyAppExeName}
@@ -113,7 +115,7 @@ Name: "{autoprograms}\{#MyAppName}"; Filename: "{app}\{#MyAppExeName}"
 Name: "{autodesktop}\{#MyAppName}"; Filename: "{app}\{#MyAppExeName}"; Tasks: desktopicon
 
 [Registry]
-Root: HKCU; Subkey: "Software\Microsoft\Windows\CurrentVersion\Run"; ValueType: string; ValueName: "{#MyAppName}"; ValueData: """{app}\{#MyAppExeName}"""; Tasks: startup; Flags: uninsdeletevalue
+Root: HKA; Subkey: "Software\Microsoft\Windows\CurrentVersion\Run"; ValueType: string; ValueName: "{#MyAppName}"; ValueData: """{app}\{#MyAppExeName}"""; Tasks: startup; Flags: uninsdeletevalue
 
 [Run]
 Filename: "{app}\{#MyAppExeName}"; Description: "{cm:LaunchProgram,{#StringChange(MyAppName, '&', '&&')}}"; Flags: nowait postinstall skipifsilent

LanMountainDesktop/plugins/PluginMarketInstallService.cs

@@ -13,6 +13,7 @@ namespace LanMountainDesktop.Views.SettingsPages;
 internal sealed class AirAppMarketInstallService : IDisposable
 {
     private readonly PluginRuntimeService _runtime;
+    private readonly PluginsInstallHelperClient _helperClient = new();
     private readonly HttpClient _httpClient;
     private readonly ResumableDownloadService _downloadService;
     private readonly AirAppMarketReleaseResolverService _releaseResolverService;
@@ -77,9 +78,13 @@ internal sealed class AirAppMarketInstallService : IDisposable
                 }
             }
 
-            await using var hashStream = File.OpenRead(downloadPath);
-            var hashBytes = await SHA256.HashDataAsync(hashStream, cancellationToken);
-            var actualHash = Convert.ToHexString(hashBytes).ToLowerInvariant();
+            string actualHash;
+            await using (var hashStream = File.OpenRead(downloadPath))
+            {
+                var hashBytes = await SHA256.HashDataAsync(hashStream, cancellationToken);
+                actualHash = Convert.ToHexString(hashBytes).ToLowerInvariant();
+            }
+
             if (!string.Equals(actualHash, plugin.Sha256, StringComparison.OrdinalIgnoreCase))
             {
                 File.Delete(downloadPath);
@@ -89,7 +94,28 @@ internal sealed class AirAppMarketInstallService : IDisposable
                     $"SHA-256 mismatch. Expected {plugin.Sha256}, actual {actualHash}.");
             }
 
-            var manifest = _runtime.InstallPluginPackage(downloadPath);
+            PluginManifest manifest;
+            if (OperatingSystem.IsWindows())
+            {
+                var helperResult = await _helperClient.InstallPackageAsync(
+                    downloadPath,
+                    _runtime.PluginsDirectory,
+                    cancellationToken);
+                if (!helperResult.Success || string.IsNullOrWhiteSpace(helperResult.InstalledPackagePath))
+                {
+                    return new AirAppMarketInstallResult(
+                        false,
+                        null,
+                        helperResult.ErrorMessage ?? "Plugins install helper failed.");
+                }
+
+                manifest = _runtime.RegisterInstalledPluginPackage(helperResult.InstalledPackagePath);
+            }
+            else
+            {
+                manifest = _runtime.InstallPluginPackage(downloadPath);
+            }
+
             AppLogger.Info(
                 "PluginMarket",
                 $"Install staged successfully. PluginId='{manifest.Id}'; InstalledName='{manifest.Name}'; PackagePath='{downloadPath}'.");

LanMountainDesktop/plugins/PluginRuntimeService.cs

@@ -21,6 +21,7 @@ public sealed class PluginRuntimeService : IDisposable
 
     private readonly PluginLoader _loader;
     private readonly AppSettingsService _appSettingsService = new();
+    private readonly IHostApplicationLifecycle _applicationLifecycle = new HostApplicationLifecycleService();
     private readonly IServiceProvider _hostServices;
     private readonly IPluginPackageManager _packageManager;
     private readonly List<LoadedPlugin> _loadedPlugins = [];
@@ -34,7 +35,7 @@ public sealed class PluginRuntimeService : IDisposable
     {
         PluginsDirectory = Path.Combine(AppContext.BaseDirectory, "Extensions", "Plugins");
         _packageManager = new PluginRuntimePackageManager(this);
-        _hostServices = new PluginHostServiceProvider(_packageManager);
+        _hostServices = new PluginHostServiceProvider(_packageManager, _applicationLifecycle);
         _loader = new PluginLoader(CreateOptions());
     }
 
@@ -196,6 +197,14 @@ public sealed class PluginRuntimeService : IDisposable
         }
     }
 
+    public PluginManifest RegisterInstalledPluginPackage(string packagePath)
+    {
+        lock (_packageMutationGate)
+        {
+            return RegisterInstalledPluginPackageCore(packagePath);
+        }
+    }
+
     public bool DeleteInstalledPlugin(string pluginId)
     {
         lock (_packageMutationGate)
@@ -288,6 +297,25 @@ public sealed class PluginRuntimeService : IDisposable
         return new PluginPackageInstallResult(manifest, replacedExisting, RestartRequired: true);
     }
 
+    private PluginManifest RegisterInstalledPluginPackageCore(string packagePath)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(packagePath);
+
+        var fullPackagePath = Path.GetFullPath(packagePath);
+        if (!File.Exists(fullPackagePath))
+        {
+            throw new FileNotFoundException($"Plugin package '{fullPackagePath}' was not found.", fullPackagePath);
+        }
+
+        var manifest = ReadManifestFromPackage(fullPackagePath);
+        AppLogger.Info(
+            "PluginRuntime",
+            $"Registering externally installed package. PluginId='{manifest.Id}'; Source='{fullPackagePath}'.");
+        UpdateCatalogAfterPackageInstall(manifest, fullPackagePath);
+        PendingRestartStateService.SetPending(PendingRestartStateService.PluginCatalogReason, true);
+        return manifest;
+    }
+
     public void Dispose()
     {
         UnloadInstalledPlugins();
@@ -652,17 +680,29 @@ public sealed class PluginRuntimeService : IDisposable
     private sealed class PluginHostServiceProvider : IServiceProvider
     {
         private readonly IPluginPackageManager _packageManager;
+        private readonly IHostApplicationLifecycle _applicationLifecycle;
 
-        public PluginHostServiceProvider(IPluginPackageManager packageManager)
+        public PluginHostServiceProvider(
+            IPluginPackageManager packageManager,
+            IHostApplicationLifecycle applicationLifecycle)
         {
             _packageManager = packageManager;
+            _applicationLifecycle = applicationLifecycle;
         }
 
         public object? GetService(Type serviceType)
         {
-            return serviceType == typeof(IPluginPackageManager)
-                ? _packageManager
-                : null;
+            if (serviceType == typeof(IPluginPackageManager))
+            {
+                return _packageManager;
+            }
+
+            if (serviceType == typeof(IHostApplicationLifecycle))
+            {
+                return _applicationLifecycle;
+            }
+
+            return null;
         }
     }