feat: implement QuestionBank CRUD with pagination and template query

- Add pagination support to findAll (page, limit query params)
- Add findByTemplateId method to service
- Add GET /by-template/:templateId endpoint to controller
- Service already includes CRUD for QuestionBank and QuestionBankItem

server/scripts/test-error-handling.d.ts

@@ -0,0 +1,2 @@
+declare function testErrorHandling(): Promise<void>;
+export { testErrorHandling };