Fix SpoolBuddy update UI responsiveness and stale data

Rewrote update button states: single `busy` flag stays set from click
  through to device pickup — no more gap with no feedback. Buttons hide
  while any operation is in progress. Listens for spoolbuddy-online
  WebSocket event to reload the page after daemon re-registers, ensuring
  fresh version and status. Set staleTime to 0 on update check queries.

frontend/src/components/spoolbuddy/SpoolBuddyLayout.tsx

@@ -64,7 +64,7 @@ export function SpoolBuddyLayout() {
     queryFn: () => device ? spoolbuddyApi.checkDaemonUpdate(device.device_id) : Promise.resolve(null),
     enabled: !!device,
     refetchInterval: 5 * 60 * 1000, // re-check every 5 minutes
-    staleTime: 30 * 1000,
+    staleTime: 0,
   });
 
   // Update alert based on device state and available updates