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.module.ts

@@ -0,0 +1,9 @@
+import { Global, Module } from '@nestjs/common';
+import { I18nService } from './i18n.service';
+
+@Global()
+@Module({
+  providers: [I18nService],
+  exports: [I18nService],
+})
+export class I18nModule {}