Replace vertical overview with dashboard composition:
- BrokerDashboardHero with portfolio KPI, return, daily change, total income
- BrokerDashboardEventsCard with compact events table and local pagination
- BrokerDashboardIncomeCard with income operations table and cursor pagination
- BrokerDashboardAnalyticsCard with analytics Metric grid
- BrokerDashboardAllocationCard wrapping existing donut chart
- BrokerDashboardSkeleton matching dashboard shape
- BrokerDashboardCard local card pattern
- Pure lib helpers: dashboardIncome, dashboardFilters, dashboardFormatters
- Unit tests for income helpers (6) and dashboard composition (1)
