Major production merge: GTK support, context menus, and dispatcher fixes

Core Infrastructure:
- Add Dispatching folder with LinuxDispatcher, LinuxDispatcherProvider, LinuxDispatcherTimer
- Add Native folder with P/Invoke wrappers (GTK, GLib, GDK, Cairo, WebKit)
- Add GTK host window system with GtkHostWindow and GtkSkiaSurfaceWidget
- Update LinuxApplication with GTK mode, theme handling, and icon support
- Fix duplicate LinuxDispatcher in LinuxMauiContext

Handlers:
- Add GtkWebViewManager and GtkWebViewPlatformView for GTK WebView
- Add FlexLayoutHandler and GestureManager
- Update multiple handlers with ToViewHandler fix and missing mappers
- Add MauiHandlerExtensions with ToViewHandler extension method

Views:
- Add SkiaContextMenu with hover, keyboard, and dark theme support
- Add LinuxDialogService with context menu management
- Add SkiaFlexLayout for flex container support
- Update SkiaShell with RefreshTheme, MauiShell, ContentRenderer
- Update SkiaWebView with SetMainWindow, ProcessGtkEvents
- Update SkiaImage with LoadFromBitmap method

Services:
- Add AppInfoService, ConnectivityService, DeviceDisplayService, DeviceInfoService
- Add GtkHostService, GtkContextMenuService, MauiIconGenerator

Window:
- Add CursorType enum and GtkHostWindow
- Update X11Window with SetIcon, SetCursor methods

Build: SUCCESS (0 errors)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Services/AppInfoService.cs

@@ -0,0 +1,142 @@
+using System;
+using System.Diagnostics;
+using System.Reflection;
+using Microsoft.Maui.ApplicationModel;
+
+namespace Microsoft.Maui.Platform.Linux.Services;
+
+public class AppInfoService : IAppInfo
+{
+    private static readonly Lazy<AppInfoService> _instance = new Lazy<AppInfoService>(() => new AppInfoService());
+
+    private readonly Assembly _entryAssembly;
+
+    private readonly string _packageName;
+
+    private readonly string _name;
+
+    private readonly string _versionString;
+
+    private readonly Version _version;
+
+    private readonly string _buildString;
+
+    public static AppInfoService Instance => _instance.Value;
+
+    public string PackageName => _packageName;
+
+    public string Name => _name;
+
+    public string VersionString => _versionString;
+
+    public Version Version => _version;
+
+    public string BuildString => _buildString;
+
+    public LayoutDirection RequestedLayoutDirection => LayoutDirection.LeftToRight;
+
+    public AppTheme RequestedTheme
+    {
+        get
+        {
+            try
+            {
+                string environmentVariable = Environment.GetEnvironmentVariable("GTK_THEME");
+                if (!string.IsNullOrEmpty(environmentVariable) && environmentVariable.Contains("dark", StringComparison.OrdinalIgnoreCase))
+                {
+                    return AppTheme.Dark;
+                }
+                if (GetGnomeColorScheme().Contains("dark", StringComparison.OrdinalIgnoreCase))
+                {
+                    return AppTheme.Dark;
+                }
+                return AppTheme.Light;
+            }
+            catch
+            {
+                return AppTheme.Light;
+            }
+        }
+    }
+
+    public AppPackagingModel PackagingModel
+    {
+        get
+        {
+            if (Environment.GetEnvironmentVariable("FLATPAK_ID") != null)
+            {
+                return AppPackagingModel.Packaged;
+            }
+            if (Environment.GetEnvironmentVariable("SNAP") != null)
+            {
+                return AppPackagingModel.Packaged;
+            }
+            if (Environment.GetEnvironmentVariable("APPIMAGE") != null)
+            {
+                return AppPackagingModel.Packaged;
+            }
+            return AppPackagingModel.Unpackaged;
+        }
+    }
+
+    public AppInfoService()
+    {
+        _entryAssembly = Assembly.GetEntryAssembly() ?? Assembly.GetExecutingAssembly();
+        _packageName = _entryAssembly.GetName().Name ?? "Unknown";
+        _name = _entryAssembly.GetCustomAttribute<AssemblyTitleAttribute>()?.Title ?? _packageName;
+        _versionString = (_version = _entryAssembly.GetName().Version ?? new Version(1, 0)).ToString();
+        _buildString = _entryAssembly.GetCustomAttribute<AssemblyInformationalVersionAttribute>()?.InformationalVersion ?? _versionString;
+    }
+
+    private string GetGnomeColorScheme()
+    {
+        try
+        {
+            using Process? process = Process.Start(new ProcessStartInfo
+            {
+                FileName = "gsettings",
+                Arguments = "get org.gnome.desktop.interface color-scheme",
+                UseShellExecute = false,
+                RedirectStandardOutput = true,
+                CreateNoWindow = true
+            });
+            if (process != null)
+            {
+                string text = process.StandardOutput.ReadToEnd();
+                process.WaitForExit(1000);
+                return text.Trim().Trim('\'');
+            }
+        }
+        catch
+        {
+        }
+        return "";
+    }
+
+    public void ShowSettingsUI()
+    {
+        try
+        {
+            Process.Start(new ProcessStartInfo
+            {
+                FileName = "gnome-control-center",
+                UseShellExecute = true
+            });
+        }
+        catch
+        {
+            try
+            {
+                Process.Start(new ProcessStartInfo
+                {
+                    FileName = "xdg-open",
+                    Arguments = "x-settings:",
+                    UseShellExecute = true
+                });
+            }
+            catch
+            {
+            }
+        }
+    }
+}