feat(app): 移除内置agents并添加CORS支持和技能上传优化

移除了agents/registry.json中的所有内置agents配置，将agents数组清空。
为web应用添加了CORS中间件支持，允许指定的前端地址跨域访问。
重构了技能上传功能，增加了LLM重写机制，自动规范化上传的技能格式。
新增了工具名称提取逻辑，从技能正文中自动识别Required Tools段落。
更新了技能学习候选者和草稿的载荷结构，添加评估报告统计信息。
修改了意图路由技能的说明，改进任务状态管理逻辑。

skills/multi-search-engine/versions/v0001/version.json

@@ -1,6 +1,6 @@
 {
   "change_reason": "Initial skill seeded from SkillHub global/multi-search-engine@20260413.065325",
-  "content_hash": "fd2d3fecd923622e6fda6c607ae4913a9a88601cbb266c7b6a25ea856e4d7f91",
+  "content_hash": "0b46644d3b97b94b0a4b8b0747165ef083e4f5a30b90f6dbea3337fd4ca48cb9",
   "created_at": "2026-06-04T09:44:11.388282+00:00",
   "created_by": "skillhub",
   "frontmatter": {
@@ -17,13 +17,13 @@
     "slug": "multi-search-engine",
     "source": "initial_skills",
     "source_kind": "initial",
-    "upstream_source": "skillhub",
-    "source_url": "https://skillhub.bwgdi.com/space/global/multi-search-engine"
+    "source_url": "https://skillhub.bwgdi.com/space/global/multi-search-engine",
+    "upstream_source": "skillhub"
   },
   "review_state": "published",
   "skill_name": "multi-search-engine",
-  "summary": "# Multi Search Engine Integration of 16 search engines for web crawling without API keys. ## Workflow",
-  "summary_hash": "214e55914a70eabf8635c1d0bd4df1f46e01f988bed9ef42070aeab6aaf12c3b",
+  "summary": "# Multi Search Engine ## Overview Multi search engine integration with 16 engines (7 CN + 9 Global). Supports advanced search operators, time filters, site search, privacy engines, and WolframAlpha knowledge queries. No API keys required.",
+  "summary_hash": "ce97577b548d0e554c02471bcf8a4082f1024ff8cd7535359713b90f655f32e5",
   "tool_hints": [
     "web_fetch"
   ],