技能展示适配:支持多结果集(result sets)渲染

- 后端 extensions_config 新增 SkillDisplayResultSetConfig,SkillDisplayConfig 增加 resultSets 字段
- threads 引用响应增加 resultSetKey / resultSetLabel,runtime/references 适配多结果集
- 前端 skill-display 适配器/运行时/类型支持多结果集渲染,聊天框、消息组、技能展示面板相应更新

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend-web/package.json

@@ -57,6 +57,7 @@
     "cmdk": "^1.1.1",
     "codemirror": "^6.0.2",
     "date-fns": "^4.1.0",
+    "dayjs": "^1.11.21",
     "docx": "^9.5.1",
     "dotenv": "^17.2.3",
     "embla-carousel-react": "^8.6.0",