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。

app-instance/backend/beaver/skills/builtin/intent-agent-router/SKILL.md

@@ -28,12 +28,13 @@ Choose `new_task` when the user asks for anything that needs the main Task agent
 
 The Intent Agent has no tools. If a request needs a tool, do not apologize and do not say you cannot access it. Route it to Task mode so the main agent can use tools.
 
-When there is an active task, do not force every new user message into that task. Use the active task and recent conversation to decide:
+When there is an active task, do not force every new user message into that task. A Session is the durable conversation/device/group context; a Task is one unit of work inside that Session. Use the active task and recent conversation to decide:
 
 - Choose `revise_task` when the user asks to change, correct, refine, expand, reformat, or redo the latest active task result.
-- Choose `continue_task` for neutral follow-up questions or additional next steps that still belong to the active task.
+- Choose `continue_task` for neutral follow-up questions or additional next steps that explicitly depend on or extend the active task's latest result.
 - Choose `simple_chat` for unrelated lightweight conversation. This starts a new topic and the previous task will be accepted automatically.
 - Choose `new_task` when the user asks for clearly unrelated work that needs Task capabilities. This starts a new topic and the previous task will be accepted automatically.
+- Choose `new_task` for a standalone tool-dependent request even when it resembles the active task. Repeating "珠海天气怎么样" later is a fresh task unless the user clearly says to continue or revise the old result.
 - Choose `close_task` when the user says the task is satisfactory or finished, such as "可以了", "就这样", or "that's good".
 - Choose `abandon_task` when the user says to stop, cancel, or no longer do the active task.
 
@@ -46,6 +47,7 @@ Examples with an active weather task:
 - "再详细一点" -> `revise_task`
 - "加上明后天穿衣建议" -> `revise_task`
 - "顺便查一下深圳" -> `continue_task`
+- "珠海天气怎么样" -> `new_task` when asked as a standalone later request
 - "帮我写一个采购合同" -> `new_task`
 - "吃饭没" -> `simple_chat`
 - "我在冰岛" -> `simple_chat`