fix.开发者调试工具设置无法正常持久化的问题。修复了插件无法进行更新的问题。

CHANGELOG.md

@@ -1,13 +1,10 @@
 # 更新日志 / Changelog
 
-## [0.8.3.4](https://github.com/yourorg/LanMountainDesktop/releases/tag/v0.8.3.4) - 2026-04-12
+## [0.8.3.5](https://github.com/yourorg/LanMountainDesktop/releases/tag/v0.8.3.5) - 2026-04-12
 
 ### 新增 (Added)
 
-- ✨ **开发者调试工具**: 新增开发者调试工具，优化插件开发体验
-  - 提供便捷的调试功能，帮助开发者快速定位和解决问题
-  - 支持插件运行时状态监控和日志查看
-  - 提升插件开发效率和调试体验
+- 无
 
 ### 变更 (Changed)
 
@@ -15,12 +12,21 @@
   - 插件开发者可以通过 View 自定义设置页面的 UI 和交互
   - 提供更灵活的设置页面展示方式，提升插件用户体验
   - 兼容原有的设置方式，平滑过渡
+- 🔧 **三指滑动与融合桌面功能开关位置调整**: 将三指滑动与融合桌面功能开关移动到了开发者设置界面
+  - 优化设置页面结构，将高级功能集中管理
+  - 普通用户界面更加简洁，开发者可在已有的开发者设置界面中访问相关设置
 
 ### 修复 (Fixed)
 
 - 🐛 **快捷方式组件透明问题**: 修复了快捷方式组件无法正常透明的问题
   - 问题原因: 组件背景透明属性设置异常或渲染层级问题
   - 修复方案: 修正透明属性配置，确保快捷方式组件背景透明效果正常显示
+- 🐛 **插件无法正常升级问题**: 修复了插件无法正常升级的问题
+  - 问题原因: 插件升级流程中存在异常，导致升级操作失败或中断
+  - 修复方案: 修复插件升级逻辑，确保插件可以正常检测、下载和安装更新
+- 🐛 **开发者设置项持久化问题**: 修复了开发者设置项不能正确持久化的问题
+  - 问题原因: 开发者设置项的保存或读取逻辑存在缺陷，导致设置无法正确保存或恢复
+  - 修复方案: 修复设置持久化逻辑，确保开发者设置项能够正确保存并在重启后恢复
 
 ### 移除 (Removed)
 

LanMountainDesktop.PluginUpgradeHelper/LanMountainDesktop.PluginUpgradeHelper.csproj

@@ -0,0 +1,16 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+    <ImplicitUsings>disable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <AssemblyName>LanMountainDesktop.PluginUpgradeHelper</AssemblyName>
+    <RootNamespace>LanMountainDesktop.PluginUpgradeHelper</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\LanMountainDesktop.PluginSdk\LanMountainDesktop.PluginSdk.csproj" />
+  </ItemGroup>
+
+</Project>

LanMountainDesktop.PluginUpgradeHelper/Program.cs

@@ -0,0 +1,372 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.IO;
+using System.IO.Compression;
+using System.Linq;
+using System.Text;
+using System.Text.Json;
+using System.Threading;
+using LanMountainDesktop.PluginSdk;
+
+namespace LanMountainDesktop.PluginUpgradeHelper;
+
+internal static class Program
+{
+    private const string PendingUpgradesFileName = ".pending-plugin-upgrades.json";
+    private const string LogFileName = "plugin-upgrade-helper.log";
+
+    private static int Main(string[] args)
+    {
+        var logPath = Path.Combine(Path.GetTempPath(), "LanMountainDesktop", LogFileName);
+        Directory.CreateDirectory(Path.GetDirectoryName(logPath)!);
+        File.AppendAllText(logPath, $"\n[{DateTime.Now:O}] PluginUpgradeHelper started. Args: {string.Join(" ", args)}\n");
+
+        try
+        {
+            var parsedArgs = ParseArgs(args);
+
+            if (!parsedArgs.TryGetValue("plugins-dir", out var pluginsDirectory) ||
+                string.IsNullOrWhiteSpace(pluginsDirectory))
+            {
+                LogError(logPath, "Missing required argument: --plugins-dir");
+                return 1;
+            }
+
+            if (!parsedArgs.TryGetValue("parent-pid", out var parentPidStr) ||
+                !int.TryParse(parentPidStr, out var parentPid))
+            {
+                LogError(logPath, "Missing or invalid argument: --parent-pid");
+                return 1;
+            }
+
+            parsedArgs.TryGetValue("launch", out var launchCommand);
+
+            LogInfo(logPath, $"Waiting for parent process {parentPid} to exit...");
+            WaitForParentProcess(parentPid);
+
+            LogInfo(logPath, $"Processing pending upgrades in '{pluginsDirectory}'...");
+            var upgradeResults = ProcessPendingUpgrades(pluginsDirectory, logPath);
+
+            LogInfo(logPath, $"Upgrades completed. Success: {upgradeResults.SuccessCount}, Failed: {upgradeResults.FailureCount}");
+
+            if (!string.IsNullOrWhiteSpace(launchCommand))
+            {
+                LogInfo(logPath, $"Launching application: {launchCommand}");
+                LaunchApplication(launchCommand, parsedArgs);
+            }
+
+            return upgradeResults.FailureCount > 0 ? 2 : 0;
+        }
+        catch (Exception ex)
+        {
+            LogError(logPath, $"Unexpected error: {ex}");
+            return 1;
+        }
+    }
+
+    private static void WaitForParentProcess(int parentPid)
+    {
+        try
+        {
+            var parentProcess = Process.GetProcessById(parentPid);
+            parentProcess.WaitForExit(TimeSpan.FromSeconds(30));
+        }
+        catch (ArgumentException)
+        {
+            // Process already exited
+        }
+        catch (Exception)
+        {
+            // Ignore errors, continue anyway
+        }
+
+        Thread.Sleep(500);
+    }
+
+    private static UpgradeResults ProcessPendingUpgrades(string pluginsDirectory, string logPath)
+    {
+        var pendingUpgradesPath = Path.Combine(pluginsDirectory, PendingUpgradesFileName);
+        var successCount = 0;
+        var failureCount = 0;
+
+        if (!File.Exists(pendingUpgradesPath))
+        {
+            LogInfo(logPath, "No pending upgrades found.");
+            return new UpgradeResults(0, 0);
+        }
+
+        List<PendingUpgrade>? pendingUpgrades;
+        try
+        {
+            var json = File.ReadAllText(pendingUpgradesPath);
+            pendingUpgrades = JsonSerializer.Deserialize<List<PendingUpgrade>>(json);
+        }
+        catch (Exception ex)
+        {
+            LogError(logPath, $"Failed to read pending upgrades: {ex.Message}");
+            return new UpgradeResults(0, 0);
+        }
+
+        if (pendingUpgrades is null || pendingUpgrades.Count == 0)
+        {
+            LogInfo(logPath, "No pending upgrades to process.");
+            return new UpgradeResults(0, 0);
+        }
+
+        Directory.CreateDirectory(pluginsDirectory);
+        var pendingDeletionDir = Path.Combine(pluginsDirectory, ".pending-deletions");
+        Directory.CreateDirectory(pendingDeletionDir);
+
+        foreach (var upgrade in pendingUpgrades)
+        {
+            if (!upgrade.IsValid())
+            {
+                LogWarn(logPath, $"Skipping invalid upgrade entry for plugin '{upgrade.PluginId}'.");
+                failureCount++;
+                continue;
+            }
+
+            try
+            {
+                LogInfo(logPath, $"Processing upgrade for plugin '{upgrade.PluginId}' to version '{upgrade.TargetVersion}'...");
+
+                var manifest = ReadManifestFromPackage(upgrade.SourcePackagePath);
+                var destinationPath = Path.Combine(pluginsDirectory, BuildInstalledPackageFileName(manifest.Id));
+
+                RemoveExistingPluginPackages(pluginsDirectory, manifest.Id, destinationPath, pendingDeletionDir, logPath);
+
+                File.Copy(upgrade.SourcePackagePath, destinationPath, overwrite: true);
+
+                LogInfo(logPath, $"Successfully upgraded plugin '{upgrade.PluginId}' to '{upgrade.TargetVersion}'.");
+                successCount++;
+            }
+            catch (Exception ex)
+            {
+                LogError(logPath, $"Failed to upgrade plugin '{upgrade.PluginId}': {ex.Message}");
+                failureCount++;
+            }
+        }
+
+        try
+        {
+            File.Delete(pendingUpgradesPath);
+        }
+        catch (Exception ex)
+        {
+            LogWarn(logPath, $"Failed to delete pending upgrades file: {ex.Message}");
+        }
+
+        CleanupPendingDeletions(pendingDeletionDir, logPath);
+
+        return new UpgradeResults(successCount, failureCount);
+    }
+
+    private static void RemoveExistingPluginPackages(
+        string pluginsDirectory,
+        string pluginId,
+        string destinationPath,
+        string pendingDeletionDir,
+        string logPath)
+    {
+        var runtimeRootDirectory = EnsureTrailingSeparator(Path.Combine(Path.GetFullPath(pluginsDirectory), ".runtime"));
+
+        foreach (var existingPackagePath in Directory
+                     .EnumerateFiles(pluginsDirectory, "*.laapp", SearchOption.AllDirectories)
+                     .Select(Path.GetFullPath)
+                     .Where(path => !path.StartsWith(runtimeRootDirectory, StringComparison.OrdinalIgnoreCase)))
+        {
+            try
+            {
+                if (string.Equals(existingPackagePath, Path.GetFullPath(destinationPath), StringComparison.OrdinalIgnoreCase))
+                {
+                    continue;
+                }
+
+                var existingManifest = ReadManifestFromPackage(existingPackagePath);
+                if (!string.Equals(existingManifest.Id, pluginId, StringComparison.OrdinalIgnoreCase))
+                {
+                    continue;
+                }
+
+                TryDeleteOrMoveFile(existingPackagePath, pendingDeletionDir, logPath);
+            }
+            catch
+            {
+                // Ignore unrelated or malformed packages
+            }
+        }
+    }
+
+    private static void TryDeleteOrMoveFile(string filePath, string pendingDeletionDir, string logPath)
+    {
+        try
+        {
+            File.Delete(filePath);
+            LogInfo(logPath, $"Deleted existing package: {filePath}");
+        }
+        catch (IOException)
+        {
+            var fileName = Path.GetFileName(filePath);
+            var pendingPath = Path.Combine(pendingDeletionDir, $"{fileName}.{Guid.NewGuid():N}.pending");
+            try
+            {
+                File.Move(filePath, pendingPath);
+                LogInfo(logPath, $"Moved existing package to pending deletion: {filePath} -> {pendingPath}");
+            }
+            catch (Exception ex)
+            {
+                LogWarn(logPath, $"Failed to move existing package '{filePath}': {ex.Message}");
+            }
+        }
+    }
+
+    private static void CleanupPendingDeletions(string pendingDeletionDir, string logPath)
+    {
+        if (!Directory.Exists(pendingDeletionDir))
+        {
+            return;
+        }
+
+        foreach (var pendingFile in Directory.EnumerateFiles(pendingDeletionDir, "*.pending"))
+        {
+            try
+            {
+                File.Delete(pendingFile);
+            }
+            catch (Exception ex)
+            {
+                LogWarn(logPath, $"Failed to delete pending file '{pendingFile}': {ex.Message}");
+            }
+        }
+
+        try
+        {
+            if (Directory.GetFiles(pendingDeletionDir).Length == 0 &&
+                Directory.GetDirectories(pendingDeletionDir).Length == 0)
+            {
+                Directory.Delete(pendingDeletionDir);
+            }
+        }
+        catch
+        {
+            // Ignore
+        }
+    }
+
+    private static void LaunchApplication(string launchCommand, Dictionary<string, string> args)
+    {
+        try
+        {
+            var startInfo = new ProcessStartInfo
+            {
+                FileName = launchCommand,
+                UseShellExecute = true,
+                WorkingDirectory = args.TryGetValue("working-dir", out var workingDir)
+                    ? workingDir
+                    : AppContext.BaseDirectory
+            };
+
+            if (args.TryGetValue("launch-args", out var launchArgs) && !string.IsNullOrWhiteSpace(launchArgs))
+            {
+                startInfo.Arguments = launchArgs;
+            }
+
+            Process.Start(startInfo);
+        }
+        catch (Exception ex)
+        {
+            Debug.WriteLine($"[PluginUpgradeHelper] Failed to launch application: {ex}");
+        }
+    }
+
+    private static PluginManifest ReadManifestFromPackage(string packagePath)
+    {
+        using var archive = ZipFile.OpenRead(packagePath);
+        var entries = archive.Entries
+            .Where(entry => string.Equals(entry.Name, "plugin.json", StringComparison.OrdinalIgnoreCase))
+            .ToArray();
+
+        if (entries.Length == 0)
+        {
+            throw new InvalidOperationException($"Plugin package '{packagePath}' does not contain 'plugin.json'.");
+        }
+
+        if (entries.Length > 1)
+        {
+            throw new InvalidOperationException($"Plugin package '{packagePath}' contains multiple 'plugin.json' files.");
+        }
+
+        using var stream = entries[0].Open();
+        return PluginManifest.Load(stream, $"{packagePath}!/{entries[0].FullName}");
+    }
+
+    private static string BuildInstalledPackageFileName(string pluginId)
+    {
+        var invalidChars = Path.GetInvalidFileNameChars();
+        var fileName = new string(pluginId.Select(ch => invalidChars.Contains(ch) ? '_' : ch).ToArray());
+        return fileName + ".laapp";
+    }
+
+    private static string EnsureTrailingSeparator(string path)
+    {
+        return path.EndsWith(Path.DirectorySeparatorChar.ToString(), StringComparison.Ordinal)
+            ? path
+            : path + Path.DirectorySeparatorChar;
+    }
+
+    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 void LogInfo(string logPath, string message)
+    {
+        File.AppendAllText(logPath, $"[{DateTime.Now:O}] [INFO] {message}\n");
+    }
+
+    private static void LogWarn(string logPath, string message)
+    {
+        File.AppendAllText(logPath, $"[{DateTime.Now:O}] [WARN] {message}\n");
+    }
+
+    private static void LogError(string logPath, string message)
+    {
+        File.AppendAllText(logPath, $"[{DateTime.Now:O}] [ERROR] {message}\n");
+    }
+
+    private sealed record PendingUpgrade(
+        string PluginId,
+        string SourcePackagePath,
+        string TargetVersion,
+        DateTimeOffset CreatedAt)
+    {
+        public bool IsValid()
+        {
+            return !string.IsNullOrWhiteSpace(PluginId) &&
+                   !string.IsNullOrWhiteSpace(SourcePackagePath) &&
+                   !string.IsNullOrWhiteSpace(TargetVersion) &&
+                   File.Exists(SourcePackagePath);
+        }
+    }
+
+    private sealed record UpgradeResults(int SuccessCount, int FailureCount);
+}

LanMountainDesktop.PluginsInstallHelper/Program.cs

@@ -135,6 +135,9 @@ internal static class Program
     private static void RemoveExistingPluginPackages(string pluginsDirectory, string pluginId, string destinationPath, string stagingPath)
     {
         var runtimeRootDirectory = EnsureTrailingSeparator(Path.Combine(Path.GetFullPath(pluginsDirectory), PluginSdkInfo.RuntimeDirectoryName));
+        var pendingDeletionDir = Path.Combine(pluginsDirectory, ".pending-deletions");
+        Directory.CreateDirectory(pendingDeletionDir);
+
         foreach (var existingPackagePath in Directory
                      .EnumerateFiles(pluginsDirectory, "*" + PluginSdkInfo.PackageFileExtension, SearchOption.AllDirectories)
                      .Select(Path.GetFullPath)
@@ -154,13 +157,58 @@ internal static class Program
                     continue;
                 }
 
-                DeleteFileWithRetry(existingPackagePath);
+                TryRemoveExistingPackage(existingPackagePath, pendingDeletionDir);
             }
             catch
             {
                 // Ignore unrelated or malformed packages while replacing an install target.
             }
         }
+
+        CleanupPendingDeletions(pendingDeletionDir);
+    }
+
+    private static void TryRemoveExistingPackage(string existingPackagePath, string pendingDeletionDir)
+    {
+        try
+        {
+            DeleteFileWithRetry(existingPackagePath);
+        }
+        catch (IOException)
+        {
+            var fileName = Path.GetFileName(existingPackagePath);
+            var pendingPath = Path.Combine(pendingDeletionDir, $"{fileName}.{Guid.NewGuid():N}.pending");
+            try
+            {
+                File.Move(existingPackagePath, pendingPath);
+            }
+            catch (IOException moveEx)
+            {
+                throw new IOException(
+                    $"Cannot delete or move existing plugin package '{existingPackagePath}'. " +
+                    $"The file may be in use by another process. Error: {moveEx.Message}", moveEx);
+            }
+        }
+    }
+
+    private static void CleanupPendingDeletions(string pendingDeletionDir)
+    {
+        if (!Directory.Exists(pendingDeletionDir))
+        {
+            return;
+        }
+
+        foreach (var pendingFile in Directory.EnumerateFiles(pendingDeletionDir, "*.pending"))
+        {
+            try
+            {
+                File.Delete(pendingFile);
+            }
+            catch
+            {
+                // Ignore cleanup failures for pending deletions.
+            }
+        }
     }
 
     private static void CopyWithRetry(string sourcePath, string destinationPath, bool overwrite)

LanMountainDesktop.slnx

@@ -8,6 +8,7 @@
   <Project Path="LanMountainDesktop.PluginSdk/LanMountainDesktop.PluginSdk.csproj" />
   <Project Path="LanMountainDesktop.PluginTemplate/LanMountainDesktop.PluginTemplate.csproj" />
   <Project Path="LanMountainDesktop.PluginsInstallHelper/LanMountainDesktop.PluginsInstallHelper.csproj" />
+  <Project Path="LanMountainDesktop.PluginUpgradeHelper/LanMountainDesktop.PluginUpgradeHelper.csproj" />
   <Project Path="LanMountainDesktop/LanMountainDesktop.csproj" />
   <Project Path="LanMountainDesktop.Tests/LanMountainDesktop.Tests.csproj" />
 </Solution>

LanMountainDesktop/App.axaml.cs

@@ -404,10 +404,7 @@ public partial class App : Application
             _traySettingsMenuItem.Header = L("tray.menu.settings", "Settings");
         }
 
-        if (_trayComponentLibraryMenuItem is not null)
-        {
-            _trayComponentLibraryMenuItem.Header = L("tray.menu.component_library", "Component Library");
-        }
+        RefreshFusedDesktopMenuItemVisibility();
 
         if (_trayRestartMenuItem is not null)
         {
@@ -420,6 +417,30 @@ public partial class App : Application
         }
     }
 
+    private void RefreshFusedDesktopMenuItemVisibility()
+    {
+        if (_trayComponentLibraryMenuItem is null)
+        {
+            return;
+        }
+
+        // 仅在 Windows 上支持融合桌面功能
+        if (!OperatingSystem.IsWindows())
+        {
+            _trayComponentLibraryMenuItem.IsVisible = false;
+            return;
+        }
+
+        // 检查融合桌面功能是否启用
+        var appSnapshot = _settingsFacade.Settings.LoadSnapshot<AppSettingsSnapshot>(SettingsScope.App);
+        _trayComponentLibraryMenuItem.IsVisible = appSnapshot.EnableFusedDesktop;
+
+        if (_trayComponentLibraryMenuItem.IsVisible)
+        {
+            _trayComponentLibraryMenuItem.Header = L("tray.menu.component_library", "Component Library");
+        }
+    }
+
     private void DisposeTrayIcon()
     {
         if (_trayIcon is null)
@@ -687,6 +708,16 @@ public partial class App : Application
                 ApplyCurrentCultureFromSettings();
                 RefreshTrayIconContent();
             }
+
+            // 检查融合桌面设置是否变更
+            var fusedDesktopChanged =
+                refreshAll ||
+                changedKeys.Contains(nameof(AppSettingsSnapshot.EnableFusedDesktop), StringComparer.OrdinalIgnoreCase);
+
+            if (fusedDesktopChanged)
+            {
+                RefreshFusedDesktopMenuItemVisibility();
+            }
         }, DispatcherPriority.Background);
     }
 

LanMountainDesktop/Models/AppSettingsSnapshot.cs

@@ -152,6 +152,8 @@ public sealed class AppSettingsSnapshot
 
     public bool EnableThreeFingerSwipe { get; set; } = false;
 
+    public bool EnableFusedDesktop { get; set; } = false;
+
     public List<string> DisabledPluginIds { get; set; } = [];
 
     public bool IsDevModeEnabled { get; set; }

LanMountainDesktop/Services/FusedDesktopManagerService.cs

@@ -58,6 +58,14 @@ internal sealed class FusedDesktopManagerService : IFusedDesktopManagerService
     {
         if (!OperatingSystem.IsWindows()) return;
         
+        // 检查融合桌面功能是否启用
+        var appSnapshot = _settingsFacade.Settings.LoadSnapshot<AppSettingsSnapshot>(SettingsScope.App);
+        if (!appSnapshot.EnableFusedDesktop)
+        {
+            AppLogger.Info("FusedDesktop", "Fused desktop is disabled. Skipping initialization.");
+            return;
+        }
+        
         EnsureRegistries();
         ReloadWidgets();
     }

LanMountainDesktop/Services/HostApplicationLifecycleService.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Diagnostics;
+using System.IO;
 using Avalonia;
 using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Threading;
@@ -9,6 +10,8 @@ namespace LanMountainDesktop.Services;
 
 public sealed class HostApplicationLifecycleService : IHostApplicationLifecycle
 {
+    private const string UpgradeHelperExecutableName = "LanMountainDesktop.PluginUpgradeHelper.exe";
+
     public bool TryExit(HostApplicationLifecycleRequest? request = null)
     {
         App? app = null;
@@ -50,28 +53,14 @@ public sealed class HostApplicationLifecycleService : IHostApplicationLifecycle
         App? app = null;
         try
         {
-            var startInfo = AppRestartService.CreateRestartStartInfo();
-            if (startInfo is null)
+            app = Application.Current as App;
+
+            if (HasPendingPluginUpgrades())
             {
-                AppLogger.Warn(
-                    "HostLifecycle",
-                    $"Restart request rejected because restart start info could not be resolved. Source='{request?.Source ?? "Unknown"}'.");
-                return false;
+                return TryRestartWithUpgradeHelper(request);
             }
 
-            Process.Start(startInfo);
-            app = Application.Current as App;
-            app?.PrepareForShutdown(isRestart: true, request?.Source ?? "Unknown");
-            var exitRequest = request is null
-                ? new HostApplicationLifecycleRequest(Reason: "Restart accepted.")
-                : request with
-                {
-                    Reason = string.IsNullOrWhiteSpace(request.Reason)
-                        ? "Restart accepted."
-                        : request.Reason
-                };
-
-            return TryExit(exitRequest);
+            return TryRestartDirectly(request);
         }
         catch (Exception ex)
         {
@@ -80,4 +69,92 @@ public sealed class HostApplicationLifecycleService : IHostApplicationLifecycle
             return false;
         }
     }
+
+    private static bool HasPendingPluginUpgrades()
+    {
+        try
+        {
+            var pluginsDirectory = Path.Combine(
+                Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
+                "LanMountainDesktop",
+                "Extensions",
+                "Plugins");
+            var pendingUpgradesPath = Path.Combine(pluginsDirectory, ".pending-plugin-upgrades.json");
+            return File.Exists(pendingUpgradesPath);
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    private bool TryRestartWithUpgradeHelper(HostApplicationLifecycleRequest? request)
+    {
+        AppLogger.Info("HostLifecycle", "Detected pending plugin upgrades. Using upgrade helper for restart.");
+
+        var helperPath = ResolveUpgradeHelperPath();
+        if (!File.Exists(helperPath))
+        {
+            AppLogger.Warn("HostLifecycle", $"Upgrade helper not found at '{helperPath}'. Falling back to direct restart.");
+            return TryRestartDirectly(request);
+        }
+
+        var pluginsDirectory = Path.Combine(
+            Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
+            "LanMountainDesktop",
+            "Extensions",
+            "Plugins");
+
+        var startInfo = AppRestartService.CreateRestartStartInfo();
+        var launchCommand = startInfo?.FileName ?? Process.GetCurrentProcess().MainModule?.FileName ?? AppContext.BaseDirectory;
+        var launchArgs = startInfo?.Arguments ?? "";
+
+        var helperStartInfo = new ProcessStartInfo
+        {
+            FileName = helperPath,
+            Arguments = $"--plugins-dir \"{pluginsDirectory}\" --parent-pid {Environment.ProcessId} --launch \"{launchCommand}\" --launch-args \"{launchArgs}\" --working-dir \"{AppContext.BaseDirectory}\"",
+            UseShellExecute = true,
+            WorkingDirectory = AppContext.BaseDirectory
+        };
+
+        AppLogger.Info("HostLifecycle", $"Starting upgrade helper: {helperStartInfo.FileName} {helperStartInfo.Arguments}");
+
+        Process.Start(helperStartInfo);
+
+        var app = Application.Current as App;
+        app?.PrepareForShutdown(isRestart: true, request?.Source ?? "Unknown");
+
+        return TryExit(request);
+    }
+
+    private bool TryRestartDirectly(HostApplicationLifecycleRequest? request)
+    {
+        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 app = Application.Current as App;
+        app?.PrepareForShutdown(isRestart: true, request?.Source ?? "Unknown");
+        var exitRequest = request is null
+            ? new HostApplicationLifecycleRequest(Reason: "Restart accepted.")
+            : request with
+            {
+                Reason = string.IsNullOrWhiteSpace(request.Reason)
+                    ? "Restart accepted."
+                    : request.Reason
+            };
+
+        return TryExit(exitRequest);
+    }
+
+    private static string ResolveUpgradeHelperPath()
+    {
+        return Path.Combine(AppContext.BaseDirectory, "PluginUpgradeHelper", UpgradeHelperExecutableName);
+    }
 }

LanMountainDesktop/Services/PendingPluginUpgradeService.cs

@@ -0,0 +1,160 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text.Json;
+using System.Threading;
+
+namespace LanMountainDesktop.Services;
+
+public sealed class PendingPluginUpgradeService
+{
+    private const string PendingUpgradesFileName = ".pending-plugin-upgrades.json";
+    private static readonly Lock Gate = new();
+    private readonly string _pendingUpgradesFilePath;
+
+    public PendingPluginUpgradeService(string pluginsDirectory)
+    {
+        _pendingUpgradesFilePath = Path.Combine(pluginsDirectory, PendingUpgradesFileName);
+    }
+
+    public IReadOnlyList<PendingPluginUpgrade> GetPendingUpgrades()
+    {
+        lock (Gate)
+        {
+            return ReadPendingUpgradesCore();
+        }
+    }
+
+    public void AddPendingUpgrade(string pluginId, string sourcePackagePath, string targetVersion)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(pluginId);
+        ArgumentException.ThrowIfNullOrWhiteSpace(sourcePackagePath);
+        ArgumentException.ThrowIfNullOrWhiteSpace(targetVersion);
+
+        lock (Gate)
+        {
+            var upgrades = ReadPendingUpgradesCore().ToList();
+
+            upgrades.RemoveAll(u =>
+                string.Equals(u.PluginId, pluginId, StringComparison.OrdinalIgnoreCase));
+
+            upgrades.Add(new PendingPluginUpgrade(
+                pluginId,
+                Path.GetFullPath(sourcePackagePath),
+                targetVersion,
+                DateTimeOffset.UtcNow));
+
+            SavePendingUpgradesCore(upgrades);
+
+            AppLogger.Info(
+                "PendingPluginUpgrade",
+                $"Added pending upgrade. PluginId='{pluginId}'; TargetVersion='{targetVersion}'; SourcePath='{sourcePackagePath}'.");
+        }
+    }
+
+    public void RemovePendingUpgrade(string pluginId)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(pluginId);
+
+        lock (Gate)
+        {
+            var upgrades = ReadPendingUpgradesCore().ToList();
+            var removed = upgrades.RemoveAll(u =>
+                string.Equals(u.PluginId, pluginId, StringComparison.OrdinalIgnoreCase));
+
+            if (removed > 0)
+            {
+                SavePendingUpgradesCore(upgrades);
+                AppLogger.Info(
+                    "PendingPluginUpgrade",
+                    $"Removed pending upgrade. PluginId='{pluginId}'.");
+            }
+        }
+    }
+
+    public void ClearPendingUpgrades()
+    {
+        lock (Gate)
+        {
+            if (File.Exists(_pendingUpgradesFilePath))
+            {
+                File.Delete(_pendingUpgradesFilePath);
+                AppLogger.Info("PendingPluginUpgrade", "Cleared all pending upgrades.");
+            }
+        }
+    }
+
+    public bool HasPendingUpgrades()
+    {
+        lock (Gate)
+        {
+            return ReadPendingUpgradesCore().Count > 0;
+        }
+    }
+
+    private List<PendingPluginUpgrade> ReadPendingUpgradesCore()
+    {
+        if (!File.Exists(_pendingUpgradesFilePath))
+        {
+            return [];
+        }
+
+        try
+        {
+            var json = File.ReadAllText(_pendingUpgradesFilePath);
+            var upgrades = JsonSerializer.Deserialize<List<PendingPluginUpgrade>>(json);
+            return upgrades?.Where(u => u.IsValid()).ToList() ?? [];
+        }
+        catch (Exception ex)
+        {
+            AppLogger.Warn(
+                "PendingPluginUpgrade",
+                $"Failed to read pending upgrades from '{_pendingUpgradesFilePath}'.",
+                ex);
+            return [];
+        }
+    }
+
+    private void SavePendingUpgradesCore(List<PendingPluginUpgrade> upgrades)
+    {
+        try
+        {
+            var directory = Path.GetDirectoryName(_pendingUpgradesFilePath);
+            if (!string.IsNullOrWhiteSpace(directory))
+            {
+                Directory.CreateDirectory(directory);
+            }
+
+            var json = JsonSerializer.Serialize(upgrades, new JsonSerializerOptions
+            {
+                WriteIndented = true
+            });
+
+            File.WriteAllText(_pendingUpgradesFilePath, json);
+        }
+        catch (Exception ex)
+        {
+            AppLogger.Error(
+                "PendingPluginUpgrade",
+                $"Failed to save pending upgrades to '{_pendingUpgradesFilePath}'.",
+                ex);
+            throw;
+        }
+    }
+}
+
+public sealed record PendingPluginUpgrade(
+    string PluginId,
+    string SourcePackagePath,
+    string TargetVersion,
+    DateTimeOffset CreatedAt)
+{
+    public bool IsValid()
+    {
+        return !string.IsNullOrWhiteSpace(PluginId) &&
+               !string.IsNullOrWhiteSpace(SourcePackagePath) &&
+               !string.IsNullOrWhiteSpace(TargetVersion) &&
+               File.Exists(SourcePackagePath);
+    }
+}

LanMountainDesktop/ViewModels/SettingsViewModels.cs

@@ -174,9 +174,6 @@ public sealed partial class GeneralSettingsPageViewModel : ViewModelBase, IDispo
         private bool _isInitializing;
         private bool _disposed;
 
-        [ObservableProperty]
-        private bool _enableThreeFingerSwipe;
-
     public GeneralSettingsPageViewModel(ISettingsFacadeService settingsFacade)
     {
         _settingsFacade = settingsFacade;
@@ -204,7 +201,6 @@ public sealed partial class GeneralSettingsPageViewModel : ViewModelBase, IDispo
         SelectedRenderMode = RenderModes.FirstOrDefault(option =>
             string.Equals(option.Value, normalizedRenderMode, StringComparison.OrdinalIgnoreCase))
             ?? RenderModes[0];
-        EnableThreeFingerSwipe = appSnapshot.EnableThreeFingerSwipe;
         _isInitializing = false;
 
         RefreshPreview();
@@ -236,33 +232,6 @@ public sealed partial class GeneralSettingsPageViewModel : ViewModelBase, IDispo
         {
             return;
         }
-        
-        // 如果是其他设置变更，重新加载我们的设置
-        _isInitializing = true;
-        try
-        {
-            var appSnapshot = _settingsFacade.Settings.LoadSnapshot<AppSettingsSnapshot>(SettingsScope.App);
-            EnableThreeFingerSwipe = appSnapshot.EnableThreeFingerSwipe;
-        }
-        finally
-        {
-            _isInitializing = false;
-        }
-    }
-
-    partial void OnEnableThreeFingerSwipeChanged(bool value)
-    {
-        if (_isInitializing)
-        {
-            return;
-        }
-
-        var appSnapshot = _settingsFacade.Settings.LoadSnapshot<AppSettingsSnapshot>(SettingsScope.App);
-        appSnapshot.EnableThreeFingerSwipe = value;
-        _settingsFacade.Settings.SaveSnapshot(
-            SettingsScope.App,
-            appSnapshot,
-            changedKeys: [nameof(AppSettingsSnapshot.EnableThreeFingerSwipe)]);
     }
 
     public event Action? RestartRequested;
@@ -3100,6 +3069,9 @@ public sealed partial class DevSettingsPageViewModel : ViewModelBase
         _isInitializing = true;
         LoadSettings();
         _isInitializing = false;
+
+        // 监听设置变更，防止被意外重置
+        _settingsFacade.Settings.Changed += OnSettingsChanged;
     }
 
     [ObservableProperty]
@@ -3108,6 +3080,12 @@ public sealed partial class DevSettingsPageViewModel : ViewModelBase
     [ObservableProperty]
     private string _devPluginPath = string.Empty;
 
+    [ObservableProperty]
+    private bool _enableThreeFingerSwipe;
+
+    [ObservableProperty]
+    private bool _enableFusedDesktop;
+
     partial void OnIsDevModeEnabledChanged(bool value)
     {
         if (_isInitializing) return;
@@ -3120,11 +3098,52 @@ public sealed partial class DevSettingsPageViewModel : ViewModelBase
         SaveField(nameof(AppSettingsSnapshot.DevPluginPath), value);
     }
 
+    partial void OnEnableThreeFingerSwipeChanged(bool value)
+    {
+        if (_isInitializing) return;
+        SaveField(nameof(AppSettingsSnapshot.EnableThreeFingerSwipe), value);
+    }
+
+    partial void OnEnableFusedDesktopChanged(bool value)
+    {
+        if (_isInitializing) return;
+        SaveField(nameof(AppSettingsSnapshot.EnableFusedDesktop), value);
+    }
+
     private void LoadSettings()
     {
         var snapshot = _settingsFacade.Settings.LoadSnapshot<AppSettingsSnapshot>(SettingsScope.App);
         IsDevModeEnabled = snapshot.IsDevModeEnabled;
         DevPluginPath = snapshot.DevPluginPath ?? string.Empty;
+        EnableThreeFingerSwipe = snapshot.EnableThreeFingerSwipe;
+        EnableFusedDesktop = snapshot.EnableFusedDesktop;
+    }
+
+    private void OnSettingsChanged(object? sender, SettingsChangedEvent e)
+    {
+        if (e.Scope != SettingsScope.App)
+        {
+            return;
+        }
+
+        var changedKeys = e.ChangedKeys?.ToArray();
+        if (changedKeys is null || changedKeys.Length == 0)
+        {
+            return;
+        }
+
+        // 如果是其他设置变更，重新加载我们的设置
+        _isInitializing = true;
+        try
+        {
+            var snapshot = _settingsFacade.Settings.LoadSnapshot<AppSettingsSnapshot>(SettingsScope.App);
+            EnableThreeFingerSwipe = snapshot.EnableThreeFingerSwipe;
+            EnableFusedDesktop = snapshot.EnableFusedDesktop;
+        }
+        finally
+        {
+            _isInitializing = false;
+        }
     }
 
     private void SaveField<T>(string key, T value)

LanMountainDesktop/Views/SettingsPages/DevSettingsPage.axaml

@@ -25,6 +25,26 @@
                 </ui:SettingsExpander.Footer>
             </ui:SettingsExpander>
 
+            <ui:SettingsExpander Header="启用三指滑动"
+                                 Description="使用三根手指或鼠标右键拖动自由滑动页面，在第一页向右滑动可回到 Windows 桌面（实验性功能）">
+                <ui:SettingsExpander.IconSource>
+                    <fi:SymbolIconSource Symbol="Gesture" />
+                </ui:SettingsExpander.IconSource>
+                <ui:SettingsExpander.Footer>
+                    <ToggleSwitch IsChecked="{Binding EnableThreeFingerSwipe}" />
+                </ui:SettingsExpander.Footer>
+            </ui:SettingsExpander>
+
+            <ui:SettingsExpander Header="启用融合桌面"
+                                 Description="允许将组件放置在 Windows 系统桌面上（实验性功能，重启后生效）">
+                <ui:SettingsExpander.IconSource>
+                    <fi:SymbolIconSource Symbol="Apps" />
+                </ui:SettingsExpander.IconSource>
+                <ui:SettingsExpander.Footer>
+                    <ToggleSwitch IsChecked="{Binding EnableFusedDesktop}" />
+                </ui:SettingsExpander.Footer>
+            </ui:SettingsExpander>
+
             <Separator Classes="settings-separator" />
 
             <ui:SettingsExpander Header="开发者插件路径"

LanMountainDesktop/Views/SettingsPages/GeneralSettingsPage.axaml

@@ -14,13 +14,6 @@
                                Text="{Binding BasicHeader}"
                                Margin="0,0,0,4" />
 
-            <ui:SettingsExpander Header="启用三指滑动"
-                                 Description="使用三根手指或鼠标右键拖动自由滑动页面，在第一页向右滑动可回到 Windows 桌面">
-                <ui:SettingsExpander.Footer>
-                    <ToggleSwitch IsChecked="{Binding EnableThreeFingerSwipe}" />
-                </ui:SettingsExpander.Footer>
-            </ui:SettingsExpander>
-
             <ui:SettingsExpander Header="{Binding LanguageHeader}">
                 <ui:SettingsExpander.IconSource>
                     <fi:SymbolIconSource Symbol="Settings" />

LanMountainDesktop/plugins/PluginMarketEmbeddedView.cs

@@ -784,12 +784,28 @@ internal sealed class PluginMarketEmbeddedView : UserControl, IDisposable
             }
 
             RefreshInstalledSnapshot();
-            SetStatus(
-                F(
-                    "market.status.install_success_format",
-                    "Plugin '{0}' has been staged. Restart the app to apply it.",
-                    result.Manifest.Name),
-                SuccessBrush);
+
+            if (result.RestartRequired)
+            {
+                SetStatus(
+                    F(
+                        "market.status.upgrade_staged_format",
+                        "Plugin '{0}' v{1} has been downloaded. Restart to complete the upgrade.",
+                        result.Manifest.Name,
+                        result.Manifest.Version),
+                    WarningBrush);
+                PendingRestartStateService.SetPending(PendingRestartStateService.PluginCatalogReason, true);
+            }
+            else
+            {
+                SetStatus(
+                    F(
+                        "market.status.install_success_format",
+                        "Plugin '{0}' has been installed successfully.",
+                        result.Manifest.Name),
+                    SuccessBrush);
+            }
+
             RebuildSurface();
         }
         catch (OperationCanceledException) when (_lifetimeCts.IsCancellationRequested)
@@ -1015,14 +1031,22 @@ internal sealed class PluginMarketEmbeddedView : UserControl, IDisposable
 
     private static int CompareVersions(string? left, string? right)
     {
-        if (!AirAppMarketIndexDocument.TryParseVersion(left, out var leftVersion))
+        var leftParsed = AirAppMarketIndexDocument.TryParseVersion(left, out var leftVersion);
+        var rightParsed = AirAppMarketIndexDocument.TryParseVersion(right, out var rightVersion);
+
+        if (!leftParsed && !rightParsed)
         {
-            leftVersion = new Version(0, 0, 0);
+            return 0;
         }
 
-        if (!AirAppMarketIndexDocument.TryParseVersion(right, out var rightVersion))
+        if (!leftParsed)
         {
-            rightVersion = new Version(0, 0, 0);
+            return -1;
+        }
+
+        if (!rightParsed)
+        {
+            return 1;
         }
 
         return (leftVersion ?? new Version(0, 0, 0)).CompareTo(rightVersion ?? new Version(0, 0, 0));

LanMountainDesktop/plugins/PluginMarketInstallService.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Net.Http;
+using System.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Security.Cryptography;
@@ -20,7 +21,9 @@ internal sealed class AirAppMarketInstallService : IDisposable
     private readonly HttpClient _httpClient;
     private readonly ResumableDownloadService _downloadService;
     private readonly AirAppMarketReleaseResolverService _releaseResolverService;
+    private readonly PendingPluginUpgradeService _pendingUpgradeService;
     private readonly string _downloadsDirectory;
+    private readonly Version? _hostVersion;
 
     public AirAppMarketInstallService(PluginRuntimeService runtime, string dataDirectory)
     {
@@ -33,6 +36,8 @@ internal sealed class AirAppMarketInstallService : IDisposable
         _httpClient.DefaultRequestHeaders.UserAgent.ParseAdd("LanMountainDesktop-PluginMarketplace/1.0");
         _downloadService = new ResumableDownloadService(_httpClient);
         _releaseResolverService = new AirAppMarketReleaseResolverService(_httpClient);
+        _pendingUpgradeService = new PendingPluginUpgradeService(runtime.PluginsDirectory);
+        _hostVersion = typeof(App).Assembly.GetName().Version;
     }
 
     public async Task<AirAppMarketInstallResult> InstallAsync(
@@ -41,18 +46,6 @@ internal sealed class AirAppMarketInstallService : IDisposable
     {
         ArgumentNullException.ThrowIfNull(plugin);
 
-        if (OperatingSystem.IsWindows())
-        {
-            var helperPath = ResolveHelperPath();
-            if (!File.Exists(helperPath))
-            {
-                return new AirAppMarketInstallResult(
-                    false,
-                    null,
-                    $"Plugins install helper was not found at '{helperPath}'.");
-            }
-        }
-
         Directory.CreateDirectory(_downloadsDirectory);
         var sources = plugin.GetPackageSourcesInInstallOrder();
         if (sources.Count == 0)
@@ -67,6 +60,39 @@ internal sealed class AirAppMarketInstallService : IDisposable
             "PluginMarket",
             $"Starting install. PluginId='{plugin.Id}'; Version='{plugin.Version}'; Sources='{string.Join(", ", sources.Select(source => source.SourceKind.ToString()))}'.");
 
+        var compatibilityError = ValidateCompatibility(plugin);
+        if (!string.IsNullOrWhiteSpace(compatibilityError))
+        {
+            AppLogger.Warn("PluginMarket", $"Compatibility check failed. PluginId='{plugin.Id}'; Error='{compatibilityError}'.");
+            return new AirAppMarketInstallResult(false, null, compatibilityError);
+        }
+
+        var isUpgrade = IsPluginInstalled(plugin.Id);
+        if (isUpgrade)
+        {
+            return await InstallUpgradeAsync(plugin, sources, cancellationToken).ConfigureAwait(false);
+        }
+
+        return await InstallNewAsync(plugin, sources, cancellationToken).ConfigureAwait(false);
+    }
+
+    private async Task<AirAppMarketInstallResult> InstallNewAsync(
+        AirAppMarketPluginEntry plugin,
+        IReadOnlyList<AirAppMarketPluginPackageSourceEntry> sources,
+        CancellationToken cancellationToken)
+    {
+        if (OperatingSystem.IsWindows())
+        {
+            var helperPath = ResolveHelperPath();
+            if (!File.Exists(helperPath))
+            {
+                return new AirAppMarketInstallResult(
+                    false,
+                    null,
+                    $"Plugins install helper was not found at '{helperPath}'.");
+            }
+        }
+
         var sourceErrors = new List<string>();
         foreach (var source in sources)
         {
@@ -93,6 +119,88 @@ internal sealed class AirAppMarketInstallService : IDisposable
         return new AirAppMarketInstallResult(false, null, combinedMessage);
     }
 
+    private async Task<AirAppMarketInstallResult> InstallUpgradeAsync(
+        AirAppMarketPluginEntry plugin,
+        IReadOnlyList<AirAppMarketPluginPackageSourceEntry> sources,
+        CancellationToken cancellationToken)
+    {
+        AppLogger.Info("PluginMarket", $"Detected upgrade scenario. Downloading package for deferred upgrade. PluginId='{plugin.Id}'.");
+
+        foreach (var source in sources)
+        {
+            var downloadResult = await DownloadPackageAsync(plugin, source, cancellationToken).ConfigureAwait(false);
+            if (downloadResult.Success && !string.IsNullOrWhiteSpace(downloadResult.PackagePath))
+            {
+                _pendingUpgradeService.AddPendingUpgrade(plugin.Id, downloadResult.PackagePath, plugin.Version);
+
+                AppLogger.Info(
+                    "PluginMarket",
+                    $"Upgrade staged for next restart. PluginId='{plugin.Id}'; Version='{plugin.Version}'; PackagePath='{downloadResult.PackagePath}'.");
+
+                var manifest = ReadManifestFromPackage(downloadResult.PackagePath);
+                return new AirAppMarketInstallResult(true, manifest, null, RestartRequired: true);
+            }
+        }
+
+        return new AirAppMarketInstallResult(
+            false,
+            null,
+            $"Failed to download upgrade package for plugin '{plugin.Id}' from all available sources.");
+    }
+
+    private bool IsPluginInstalled(string pluginId)
+    {
+        return _runtime.Catalog.Any(entry =>
+            string.Equals(entry.Manifest.Id, pluginId, StringComparison.OrdinalIgnoreCase));
+    }
+
+    private string? ValidateCompatibility(AirAppMarketPluginEntry plugin)
+    {
+        if (_hostVersion is null)
+        {
+            return null;
+        }
+
+        if (!string.IsNullOrWhiteSpace(plugin.MinHostVersion))
+        {
+            if (!AirAppMarketIndexDocument.TryParseVersion(plugin.MinHostVersion, out var minHostVersion) ||
+                minHostVersion is null)
+            {
+                return $"Plugin '{plugin.Id}' declares invalid minimum host version '{plugin.MinHostVersion}'.";
+            }
+
+            if (_hostVersion < minHostVersion)
+            {
+                return $"Plugin '{plugin.Id}' requires host version {plugin.MinHostVersion} or newer. Current host version is {_hostVersion}.";
+            }
+        }
+
+        if (!string.IsNullOrWhiteSpace(plugin.ApiVersion))
+        {
+            if (!AirAppMarketIndexDocument.TryParseVersion(plugin.ApiVersion, out var pluginApiVersion) ||
+                pluginApiVersion is null)
+            {
+                return $"Plugin '{plugin.Id}' declares invalid API version '{plugin.ApiVersion}'.";
+            }
+
+            var hostApiVersion = PluginSdkInfo.ApiVersion;
+            if (hostApiVersion is not null)
+            {
+                if (!AirAppMarketIndexDocument.TryParseVersion(hostApiVersion, out var hostApiVersionParsed) ||
+                    hostApiVersionParsed is null)
+                {
+                    AppLogger.Warn("PluginMarket", $"Host API version '{hostApiVersion}' could not be parsed. Skipping API version check.");
+                }
+                else if (pluginApiVersion.Major != hostApiVersionParsed.Major)
+                {
+                    return $"Plugin '{plugin.Id}' uses incompatible API version {plugin.ApiVersion}. Host API version is {hostApiVersion}. Major version must match.";
+                }
+            }
+        }
+
+        return null;
+    }
+
     private async Task<AirAppMarketInstallAttemptResult> TryInstallFromSourceAsync(
         AirAppMarketPluginEntry plugin,
         AirAppMarketPluginPackageSourceEntry source,
@@ -275,6 +383,71 @@ internal sealed class AirAppMarketInstallService : IDisposable
         }
     }
 
+    private async Task<DownloadPackageResult> DownloadPackageAsync(
+        AirAppMarketPluginEntry plugin,
+        AirAppMarketPluginPackageSourceEntry source,
+        CancellationToken cancellationToken)
+    {
+        var packagePath = Path.Combine(
+            _downloadsDirectory,
+            $"{SanitizeFileName(plugin.Id)}-{SanitizeFileName(plugin.Version)}-{SanitizeFileName(source.SourceKind.ToString())}-{Guid.NewGuid():N}.laapp");
+
+        try
+        {
+            var resolvedDownloadUrl = await _releaseResolverService.ResolveDownloadUrlAsync(plugin, source, cancellationToken).ConfigureAwait(false);
+            AppLogger.Info(
+                "PluginMarket",
+                $"Downloading upgrade package for '{plugin.Id}' from '{resolvedDownloadUrl}'.");
+
+            var acquireResult = await AcquirePackageAsync(plugin, source, resolvedDownloadUrl, packagePath, cancellationToken).ConfigureAwait(false);
+            if (!acquireResult.Success)
+            {
+                TryDeleteFile(packagePath);
+                return new DownloadPackageResult(false, null, acquireResult.ErrorMessage);
+            }
+
+            var verificationResult = await VerifyPackageAsync(plugin, packagePath, cancellationToken).ConfigureAwait(false);
+            if (!verificationResult.Success)
+            {
+                TryDeleteFile(packagePath);
+                return new DownloadPackageResult(false, null, verificationResult.ErrorMessage);
+            }
+
+            return new DownloadPackageResult(true, packagePath, null);
+        }
+        catch (OperationCanceledException)
+        {
+            TryDeleteFile(packagePath);
+            throw;
+        }
+        catch (Exception ex)
+        {
+            TryDeleteFile(packagePath);
+            return new DownloadPackageResult(false, null, ex.Message);
+        }
+    }
+
+    private static PluginManifest ReadManifestFromPackage(string packagePath)
+    {
+        using var archive = System.IO.Compression.ZipFile.OpenRead(packagePath);
+        var entries = archive.Entries
+            .Where(entry => string.Equals(entry.Name, "plugin.json", StringComparison.OrdinalIgnoreCase))
+            .ToArray();
+
+        if (entries.Length == 0)
+        {
+            throw new InvalidOperationException($"Plugin package '{packagePath}' does not contain 'plugin.json'.");
+        }
+
+        if (entries.Length > 1)
+        {
+            throw new InvalidOperationException($"Plugin package '{packagePath}' contains multiple 'plugin.json' files.");
+        }
+
+        using var stream = entries[0].Open();
+        return PluginManifest.Load(stream, $"{packagePath}!/{entries[0].FullName}");
+    }
+
     public void Dispose()
     {
         _httpClient.Dispose();
@@ -299,4 +472,9 @@ internal sealed class AirAppMarketInstallService : IDisposable
     private sealed record AirAppMarketVerificationResult(
         bool Success,
         string? ErrorMessage);
+
+    private sealed record DownloadPackageResult(
+        bool Success,
+        string? PackagePath,
+        string? ErrorMessage);
 }

LanMountainDesktop/plugins/PluginMarketModels.cs

@@ -305,7 +305,8 @@ internal sealed record AirAppMarketLoadResult(
 internal sealed record AirAppMarketInstallResult(
     bool Success,
     PluginManifest? Manifest,
-    string? ErrorMessage);
+    string? ErrorMessage,
+    bool RestartRequired = false);
 
 internal sealed class AirAppMarketIndexDocument
 {

LanMountainDesktop/plugins/PluginRuntimeService.cs

@@ -773,11 +773,6 @@ public sealed class PluginRuntimeService : IDisposable
     private void ApplyPendingPluginDeletions()
     {
         var pendingPaths = ReadPendingPluginDeletions();
-        if (pendingPaths.Count == 0)
-        {
-            return;
-        }
-
         var remainingPaths = new List<string>();
         foreach (var path in pendingPaths)
         {
@@ -788,6 +783,41 @@ public sealed class PluginRuntimeService : IDisposable
         }
 
         SavePendingPluginDeletions(remainingPaths);
+        CleanupPendingDeletionDirectory();
+    }
+
+    private void CleanupPendingDeletionDirectory()
+    {
+        var pendingDeletionDir = Path.Combine(PluginsDirectory, ".pending-deletions");
+        if (!Directory.Exists(pendingDeletionDir))
+        {
+            return;
+        }
+
+        foreach (var pendingFile in Directory.EnumerateFiles(pendingDeletionDir, "*.pending"))
+        {
+            try
+            {
+                File.Delete(pendingFile);
+            }
+            catch
+            {
+                // Ignore cleanup failures for pending deletions.
+            }
+        }
+
+        try
+        {
+            if (Directory.GetFiles(pendingDeletionDir).Length == 0 &&
+                Directory.GetDirectories(pendingDeletionDir).Length == 0)
+            {
+                Directory.Delete(pendingDeletionDir);
+            }
+        }
+        catch
+        {
+            // Ignore directory cleanup failures.
+        }
     }
 
     private string ResolvePluginRemovalTargetPath(PluginCatalogEntry entry)