Just unregistering the SW wasn't enough — the old SW still controlled
the page for that load. Now detects if any SW exists, nukes all SWs
and caches, then reloads once to get a clean fetch from the server.
Subsequent loads skip this since no SW is registered.
The kiosk touchscreen has no way to hard-refresh, and the service worker
served stale cached JS after updates. SpoolBuddy pages now unregister
any existing SW and skip registration entirely. Regular desktop/mobile
users still get the SW. Restored kiosk restart in SSH update flow since
SW is no longer an obstacle.
maziggy