新增 SQL 题型前端支持

- LANGUAGE 类型与六张语言映射表补 SQL；编辑器 SQLite 方言高亮
- 出题表单：SQL 语言选项、题型/行序配置卡片、数据脚本压缩包上传、标准答案必填校验
- 修复做题页语言回退硬编码 Python3 的问题（SQL 题会提交被拒）
- SQL 题隐藏自测猫/自测屏/复制到自测猫（外部运行器不支持 SQL）

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

package.json

@@ -13,6 +13,7 @@
     "@codemirror/autocomplete": "^6.20.3",
     "@codemirror/lang-cpp": "^6.0.3",
     "@codemirror/lang-python": "^6.2.1",
+    "@codemirror/lang-sql": "^6.10.0",
     "@vue-flow/background": "^1.3.2",
     "@vue-flow/controls": "^1.1.3",
     "@vue-flow/core": "^1.48.2",