fix: remove bank PUBLISHED guard from selectQuestions

selectQuestions now only checks item-level PUBLISHED status.
startSession already handles bank detection by counting published items.
This fixes assessment always falling back to LLM generation.

server/src/assessment/services/question-bank.service.ts

@@ -525,11 +525,6 @@ export class QuestionBankService {
     count: number,
   ): Promise<QuestionBankItem[]> {
     const bank = await this.findOne(bankId);
-    if (bank.status !== QuestionBankStatus.PUBLISHED) {
-      throw new ForbiddenException(
-        'Only PUBLISHED banks can be used for selection',
-      );
-    }
 
     const allItems = await this.itemRepository.find({
       where: { bankId, status: QuestionBankItemStatus.PUBLISHED },