feat(installer): optionally register ClaudeDo MCP server with Claude

Add an install step and welcome-page opt-in that registers the ClaudeDo
external MCP server with the Claude CLI. Failures are non-fatal and surface
the manual command so a missing or old CLI never blocks the install.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/ClaudeDo.Installer/Pages/InstallPage/InstallPageViewModel.cs

@@ -148,6 +148,7 @@ public partial class InstallPageViewModel : ObservableObject, IInstallerPage
                     _serviceProvider.GetRequiredService<DownloadAndExtractStep>(),
                     // Migrates the legacy service away and (re)registers the logon task.
                     _serviceProvider.GetRequiredService<RegisterAutostartStep>(),
+                    _serviceProvider.GetRequiredService<RegisterMcpStep>(),
                     _serviceProvider.GetRequiredService<StartWorkerStep>(),
                     _serviceProvider.GetRequiredService<WriteInstallManifestStep>(),
                     // Refresh the bundled uninstaller exe + Add/Remove-Programs version so a

src/ClaudeDo.Installer/Pages/WelcomePage/WelcomePageView.xaml

@@ -32,6 +32,14 @@
             <TextBlock Text="{Binding InstallError}" Foreground="{StaticResource ErrorBrush}" FontSize="11"
                        Visibility="{Binding InstallError, Converter={StaticResource NullToCollapsedConverter}}"/>
 
+            <CheckBox Content="Register MCP server with Claude"
+                      IsChecked="{Binding RegisterMcp}"
+                      Margin="0,24,0,0"/>
+            <TextBlock Text="Runs 'claude mcp add' so Claude can view and manage your ClaudeDo tasks. You can change this later."
+                       TextWrapping="Wrap" FontSize="11"
+                       Foreground="{StaticResource TextSecondaryBrush}"
+                       Margin="0,4,0,0"/>
+
         </StackPanel>
     </ScrollViewer>
 </UserControl>

src/ClaudeDo.Installer/Pages/WelcomePage/WelcomePageViewModel.cs

@@ -24,6 +24,7 @@ public partial class WelcomePageViewModel : ObservableObject, IInstallerPage
     [ObservableProperty] private string _heading = "Install ClaudeDo";
     [ObservableProperty] private string _subheading = "Set the installation directory and continue.";
     [ObservableProperty] private bool _installDirEditable = true;
+    [ObservableProperty] private bool _registerMcp = true;
 
     public WelcomePageViewModel(InstallContext context)
     {
@@ -62,6 +63,7 @@ public partial class WelcomePageViewModel : ObservableObject, IInstallerPage
     public Task ApplyAsync()
     {
         _context.InstallDirectory = InstallDirectory;
+        _context.RegisterMcpWithClaude = RegisterMcp;
         return Task.CompletedTask;
     }