BrokerDashboardCard previously rendered <Heading level={3} size="section">,
which produced an <h3> under the <h1> account name in BrokerAccountLayout,
skipping the <h2> level. Use level={2} so the semantic HTML is a proper
<h2> while keeping the compact "section" visual size.
Also extract the byte-identical toolbar wrapper (grid + chips + date filter
slot) shared by BrokerDashboardEventsCard and BrokerDashboardIncomeCard
into BrokerDashboardTableToolbar to remove duplicated sx config.
Sergey Krylov
21df354df6