docs: add account income analytics

architecture/system-overview.md

@@ -11,7 +11,8 @@ WealthLedger — локальное приложение для просмотр
   token на User.
 - [Брокерские счета](../features/brokerage-accounts.md),
   [Portfolio](../features/portfolio-view.md),
-  [Account Ledger](../features/brokerage-account-ledger.md) и
+  [Account Ledger](../features/brokerage-account-ledger.md),
+  [Пассивный доход](../features/brokerage-account-income-analytics.md) и
   [Future Cash Events](../features/brokerage-account-upcoming-events.md).
 - [Frontend UI resilience](../features/frontend-ui-resilience.md): явные
   loading, error, empty и cached-snapshot состояния; initial и частичные