Fix Preferences missing from the standard app menu: 1.8.1's workaround for
LSUIElement (plain Window + openWindow) was never swapped back for a real
Settings{} scene after 1.8.2 removed LSUIElement, so there was still no
Preferences item in the app's own menu or Cmd+, binding, only a button in
the main window and a menu-bar-dropdown item. Restored Settings{} now that
the app menu exists to host it; menu bar dropdown and main window button
both use the standard openSettings()/SettingsLink instead of a custom
openWindow(id:). Net simplification -- removes the now-redundant window ID
and controller method.
All unit tests pass.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>