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/src/i18n/i18n.store.ts

@@ -0,0 +1,7 @@
+import { AsyncLocalStorage } from 'async_hooks';
+
+export interface I18nContext {
+  language: string;
+}
+
+export const i18nStore = new AsyncLocalStorage<I18nContext>();