chore: remove dashboard auto-refresh footer text (refs #178)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/features/dashboard/components/DashboardScreen.tsx

@@ -135,13 +135,6 @@ export const DashboardScreen: React.FC<DashboardScreenProps> = ({
         onViewVehicles={() => onNavigate?.('Vehicles')}
       />
 
-      {/* Footer Hint */}
-      <div className="text-center py-4">
-        <p className="text-xs text-slate-400 dark:text-canna">
-          Dashboard updates every 2 minutes
-        </p>
-      </div>
-
       {/* Pending Receipts Dialog */}
       <Dialog
         open={showPendingReceipts}