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

nginx/generate-ssl.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+# 生成自签名 SSL 证书
+openssl req -x509 -nodes -days 365 -newkey rsa:2048 \
+    -keyout nginx/ssl/key.pem \
+    -out nginx/ssl/cert.pem \
+    -subj "/C=CN/ST=Beijing/L=Beijing/O=SimpleKB/CN=localhost"
+
+echo "SSL 证书已生成到 nginx/ssl/ 目录"
+echo "注意: 这是自签名证书，浏览器会显示安全警告"
+echo "生产环境请使用 Let's Encrypt 或购买正式证书"