refactor: organize backend by business responsibility

src/modules/investments/instruments/stocks/application/stock-position.ts

@@ -0,0 +1,5 @@
+import type { PortfolioDto } from '../../../portfolio/portfolio.api';
+import { instrumentPosition } from '../../application/instrument-position';
+export function stockPosition(portfolio: PortfolioDto, uid: string) {
+  return instrumentPosition(portfolio, uid, 'STOCK');
+}