feat(installer): show version info and offer worker restart in settings

- Surface Latest version and flag unparseable pre-release tags in
  VersionLabel so users know why auto-update was skipped.
- Prompt to stop/start the worker service after Save, since the
  worker only reads its config at process start.

src/ClaudeDo.Installer/Views/SettingsViewModel.cs

@@ -50,7 +50,12 @@ public partial class SettingsViewModel : ObservableObject
         _uninstallRunner = uninstallRunner;
         _selectedPage = Pages.FirstOrDefault();
 
-        VersionLabel = $"Installed: {context.InstalledVersion ?? "?"}   Installer: {context.InstallerVersion ?? "?"}";
+        var label = $"Installed: {context.InstalledVersion ?? "?"}   Installer: {context.InstallerVersion ?? "?"}";
+        if (!string.IsNullOrEmpty(context.LatestVersion))
+            label += $"   Latest: {context.LatestVersion}";
+        if (context.LatestTagUnparseable)
+            label += "   (pre-release tag — auto-update disabled)";
+        VersionLabel = label;
 
         _ = LoadAllAsync();
     }
@@ -98,8 +103,39 @@ public partial class SettingsViewModel : ObservableObject
         };
         uiCfg.Save();
 
-        StatusMessage = "Settings saved.";
         IsStatusError = false;
+        StatusMessage = "Settings saved.";
+
+        // Worker reads its config at process start, so changes only take effect after a restart.
+        var restart = MessageBox.Show(
+            "Restart the worker service now so the new settings take effect?",
+            "Restart Worker",
+            MessageBoxButton.YesNo,
+            MessageBoxImage.Question);
+
+        if (restart != MessageBoxResult.Yes)
+        {
+            StatusMessage = "Settings saved. Restart the worker service manually to apply.";
+            return;
+        }
+
+        var progress = new Progress<string>(msg => StatusMessage = msg);
+        var stop = await _stopService.ExecuteAsync(_context, progress, CancellationToken.None);
+        if (!stop.Success)
+        {
+            StatusMessage = $"Saved, but worker stop failed: {stop.ErrorMessage}";
+            IsStatusError = true;
+            return;
+        }
+        var start = await _startService.ExecuteAsync(_context, progress, CancellationToken.None);
+        if (!start.Success)
+        {
+            StatusMessage = $"Saved, but worker start failed: {start.ErrorMessage}";
+            IsStatusError = true;
+            return;
+        }
+
+        StatusMessage = "Settings saved. Worker restarted.";
     }
 
     [RelayCommand]