feat(ui): add About modal opened from Help menu

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/ClaudeDo.Ui/ViewModels/IslandsShellViewModel.cs

@@ -8,6 +8,7 @@ using ClaudeDo.Data;
 using ClaudeDo.Data.Models;
 using ClaudeDo.Ui.Services;
 using ClaudeDo.Ui.ViewModels.Islands;
+using ClaudeDo.Ui.ViewModels.Modals;
 using ClaudeDo.Ui.ViewModels.Planning;
 using Microsoft.EntityFrameworkCore;
 
@@ -35,6 +36,9 @@ public sealed partial class IslandsShellViewModel : ViewModelBase
     // Set by MainWindow to open the conflict resolution dialog.
     public Func<ConflictResolutionViewModel, Task>? ShowConflictDialog { get; set; }
 
+    // Set by MainWindow to open the About dialog.
+    public Func<AboutModalViewModel, Task>? ShowAboutModal { get; set; }
+
     [ObservableProperty] private bool _isUpdateBannerVisible;
     [ObservableProperty] private string? _updateBannerLatestVersion;
     [ObservableProperty] private string? _inlineUpdateStatus;
@@ -222,6 +226,13 @@ public sealed partial class IslandsShellViewModel : ViewModelBase
         if (InlineUpdateStatus == text) InlineUpdateStatus = null;
     }
 
+    [RelayCommand]
+    private async Task OpenAbout()
+    {
+        var vm = new AboutModalViewModel();
+        if (ShowAboutModal is not null) await ShowAboutModal(vm);
+    }
+
     [RelayCommand]
     private async Task CheckForUpdatesAsync()
     {

src/ClaudeDo.Ui/ViewModels/Modals/AboutModalViewModel.cs

@@ -0,0 +1,34 @@
+using System.Diagnostics;
+using System.IO;
+using System.Reflection;
+using ClaudeDo.Data;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+
+namespace ClaudeDo.Ui.ViewModels.Modals;
+
+public sealed partial class AboutModalViewModel : ViewModelBase
+{
+    public string AppVersion { get; } =
+        Assembly.GetExecutingAssembly().GetName().Version?.ToString(3) ?? "0.0.0";
+    public string DataFolderPath { get; } = Paths.AppDataRoot();
+    public string LogsFolderPath { get; } = Path.Combine(Paths.AppDataRoot(), "logs");
+    public string WorkerConfigPath { get; } = Path.Combine(Paths.AppDataRoot(), "worker.config.json");
+
+    public Action? CloseAction { get; set; }
+
+    [RelayCommand] private void Close() => CloseAction?.Invoke();
+
+    [RelayCommand]
+    private void OpenPath(string? path)
+    {
+        if (string.IsNullOrWhiteSpace(path)) return;
+        try
+        {
+            var target = File.Exists(path) ? path : (Directory.Exists(path) ? path : null);
+            if (target is null) return;
+            Process.Start(new ProcessStartInfo("explorer.exe", $"\"{target}\"") { UseShellExecute = true });
+        }
+        catch { /* ignore */ }
+    }
+}