feat: add stock details and ticker resolution

Expose stock search, market data, company information, dividends and portfolio history with exact instrument identity and verified ticker aliases. Include stock and bond position counts in account summaries.

src/tbank/brokerage-account.dto.ts

@@ -4,6 +4,20 @@ import { MoneyDto } from './portfolio.dto';
 export class PortfolioSummaryDto {
   @ApiProperty({ type: MoneyDto, isArray: true })
   totalsByCurrency: MoneyDto[];
+
+  @ApiProperty({
+    type: 'integer',
+    minimum: 0,
+    description: 'Number of non-zero stock positions, not the number of units.',
+  })
+  stockPositionCount: number;
+
+  @ApiProperty({
+    type: 'integer',
+    minimum: 0,
+    description: 'Number of non-zero bond positions, not the number of units.',
+  })
+  bondPositionCount: number;
 }
 
 export class BrokerageAccountDto {