Recreate the gold-rimmed 'PS' typewriter-tile emblem as scalable SVGs:
- public/logo.svg — dark-ground emblem used as the app favicon
- public/logo-mark.svg — transparent mark placed in the Topbar beside
the page title, with a subtle hover scale
Add <link rel=icon> to index.html and a .ps-topbar-logo rule in
AppShell.css.