refactor: organize backend by business responsibility

src/modules/investments/account-reference.dto.ts

@@ -0,0 +1,10 @@
+import { ApiProperty } from '@nestjs/swagger';
+
+/** Source account of a row in an all-accounts response. */
+export class AccountReferenceDto {
+  @ApiProperty()
+  declare id: string;
+
+  @ApiProperty()
+  declare name: string;
+}