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/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";