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/frontend/lib/api.ts

@@ -58,6 +58,7 @@ const WS_URL = process.env.NEXT_PUBLIC_WS_URL?.trim();
 const DEFAULT_API_URL = 'http://127.0.0.1:18080';
 const ACCESS_TOKEN_KEY = 'beaver_access_token';
 const REFRESH_TOKEN_KEY = 'beaver_refresh_token';
+export const AUTH_CLEARED_EVENT = 'beaver-auth-cleared';
 const REQUEST_TIMEOUT_MS = 8000;
 const OUTLOOK_REQUEST_TIMEOUT_MS = 45000;
 const SKILL_LEARNING_REQUEST_TIMEOUT_MS = 120000;
@@ -117,6 +118,34 @@ type FetchJsonOptions = RequestInit & {
   timeoutMs?: number;
 };
 
+export class ApiError extends Error {
+  status: number;
+  detail: string;
+
+  constructor(message: string, options: { status: number; detail: string }) {
+    super(message);
+    this.name = 'ApiError';
+    this.status = options.status;
+    this.detail = options.detail;
+  }
+}
+
+export function isApiError(error: unknown, status?: number): error is ApiError {
+  return error instanceof ApiError && (status === undefined || error.status === status);
+}
+
+function parseErrorDetail(text: string): string {
+  try {
+    const parsed = JSON.parse(text);
+    if (parsed && typeof parsed.detail === 'string') {
+      return parsed.detail;
+    }
+  } catch {
+    // keep raw text
+  }
+  return text;
+}
+
 function withTimeout(
   signal?: AbortSignal,
   timeoutMs: number = REQUEST_TIMEOUT_MS
@@ -163,6 +192,7 @@ export function clearTokens(): void {
   if (!isBrowser()) return;
   localStorage.removeItem(ACCESS_TOKEN_KEY);
   localStorage.removeItem(REFRESH_TOKEN_KEY);
+  window.dispatchEvent(new CustomEvent(AUTH_CLEARED_EVENT));
 }
 
 export function isLoggedIn(): boolean {
@@ -215,16 +245,11 @@ async function fetchJSON<T>(path: string, options?: FetchJsonOptions): Promise<T
     if (res.status === 401) {
       clearTokens();
     }
-    let detail = text;
-    try {
-      const parsed = JSON.parse(text);
-      if (parsed && typeof parsed.detail === 'string') {
-        detail = parsed.detail;
-      }
-    } catch {
-      // keep raw text
-    }
-    throw new Error(`${pickAppText(locale, '接口错误', 'API error')} ${res.status}: ${detail}`);
+    const detail = parseErrorDetail(text);
+    throw new ApiError(`${pickAppText(locale, '接口错误', 'API error')} ${res.status}: ${detail}`, {
+      status: res.status,
+      detail,
+    });
   }
   return res.json();
 }
@@ -1216,7 +1241,7 @@ export async function uploadSkill(file: File): Promise<Skill> {
 
   if (!res.ok) {
     const text = await res.text();
-    throw new Error(`接口错误 ${res.status}: ${text}`);
+    throw new Error(`接口错误 ${res.status}: ${parseErrorDetail(text)}`);
   }
   return res.json();
 }