feat(frontend): allow aria-label on BrokerDashboardCard

Support setting an accessible name on the dashboard card section so
consumers can query sections via getByLabelText in tests and assistive
tech, matching the hero pattern in BrokerDashboardHero.

apps/frontend/src/widgets/broker-dashboard/ui/BrokerDashboardCard.tsx

@@ -8,6 +8,7 @@ type BrokerDashboardCardProps = {
   filters?: ReactNode
   children: ReactNode
   sx?: SxProps<Theme>
+  ariaLabel?: string
 }
 
 export function BrokerDashboardCard({
@@ -16,10 +17,12 @@ export function BrokerDashboardCard({
   filters,
   children,
   sx,
+  ariaLabel,
 }: BrokerDashboardCardProps) {
   return (
     <Box
       component="section"
+      aria-label={ariaLabel}
       sx={{
         border: '1px solid',
         borderColor: 'divider',