Enhance branch management with foreign key relation handling

- Updated `BranchesModule` to include foreign key relations in list and write responses, ensuring they are represented as nested objects using `pickRelation`.
- Introduced new `relation-response.mdc` file to define guidelines for embedding foreign key relations.
- Modified `BranchesRepository` to support fetching related `division`, `createdByUser`, and `updatedByUser` data.
- Updated DTOs and service methods to reflect changes in response structure, removing direct foreign key IDs.
- Added unit tests to validate the new relation handling in branches service and repository.
- Enhanced e2e tests to verify the correct structure of branch responses with nested relations.

src/common/http/response/index.ts

@@ -22,3 +22,13 @@ export {
   PAGINATION_DEFAULT_LIMIT,
   PAGINATION_MAX_LIMIT,
 } from './pagination.constants';
+export {
+  DEFAULT_RELATION_FIELDS,
+  pickDefaultRelation,
+  pickRelation,
+  pickUserRelation,
+  USER_RELATION_FIELDS,
+  type DefaultRelation,
+  type UserRelation,
+} from './relation-fields';
+export { DefaultRelationDto, UserRelationDto } from './relation.dto';