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/App.xaml.cs

@@ -50,6 +50,7 @@ public partial class App : Application
         context.Mode = state.Mode;
         context.InstalledVersion = state.Existing?.Version;
         context.LatestVersion = state.LatestVersion;
+        context.LatestTagUnparseable = state.LatestTagUnparseable;
         if (state.Existing is not null)
             context.InstallDirectory = state.Existing.InstallDir;
 

src/ClaudeDo.Installer/Core/InstallContext.cs

@@ -10,6 +10,7 @@ public sealed class InstallContext
     public string? InstallerVersion { get; set; }   // from this installer's assembly
     public string? InstalledVersion { get; set; }   // from install.json (or set by DownloadAndExtractStep)
     public string? LatestVersion { get; set; }      // from Gitea API (may be null if offline)
+    public bool LatestTagUnparseable { get; set; }   // true if latest tag isn't a System.Version
 
     // PathsPage
     public string DbPath { get; set; } = "~/.todo-app/todo.db";

src/ClaudeDo.Installer/Core/InstallModeDetector.cs

@@ -4,7 +4,12 @@ public sealed record DetectedState(
     InstallerMode Mode,
     InstallManifest? Existing,
     GiteaRelease? LatestRelease,
-    string? LatestVersion);
+    string? LatestVersion)
+{
+    /// <summary>True when a release was returned but its tag isn't a parseable
+    /// System.Version (e.g. "0.2.0-beta") — so we couldn't decide if it's newer.</summary>
+    public bool LatestTagUnparseable { get; init; }
+}
 
 public sealed class InstallModeDetector
 {
@@ -26,23 +31,26 @@ public sealed class InstallModeDetector
             return new DetectedState(InstallerMode.Config, manifest, null, null);
 
         var latestVersion = release.TagName.TrimStart('v', 'V');
-        if (IsNewer(latestVersion, manifest.Version))
+        var newer = IsNewer(latestVersion, manifest.Version, out var unparseable);
+        if (newer)
             return new DetectedState(InstallerMode.Update, manifest, release, latestVersion);
 
-        return new DetectedState(InstallerMode.Config, manifest, release, latestVersion);
+        return new DetectedState(InstallerMode.Config, manifest, release, latestVersion)
+        {
+            LatestTagUnparseable = unparseable,
+        };
     }
 
     /// <summary>
     /// Returns true only when both versions parse as System.Version (major.minor[.build[.revision]])
     /// AND latest &gt; current. Semver pre-release tags like "0.2.0-beta" fail to parse and are
-    /// treated as "not newer" — the user drops into Config mode with no update offered.
-    /// This is deliberate: offering an update we can't compare is worse than silently skipping it.
-    /// If the project starts shipping pre-release tags, revisit this.
+    /// treated as "not newer" — the user drops into Config mode with no update offered, but
+    /// <paramref name="unparseable"/> is set so the UI can surface a hint.
     /// </summary>
-    private static bool IsNewer(string latest, string current)
+    private static bool IsNewer(string latest, string current, out bool unparseable)
     {
-        if (!Version.TryParse(latest, out var lv)) return false;
-        if (!Version.TryParse(current, out var cv)) return false;
+        unparseable = !Version.TryParse(latest, out var lv) | !Version.TryParse(current, out var cv);
+        if (unparseable) return false;
         return lv > cv;
     }
 }

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]