fix: 修复 Claude 代理对智谱 AI 的认证兼容

- 将 x-api-key 头自动转换为 Authorization: Bearer 格式
- 检测上游是否为智谱 AI，自动适配认证方式
- 保持标准 Claude API 认证头的直接透传

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

src/proxy.ts

@@ -16,15 +16,42 @@ function getBaseUrl(): string {
   return process.env.ANTHROPIC_BASE_URL || 'https://api.anthropic.com';
 }
 
-// 提取需要透传的 headers
+// 提取需要透传的 headers，并处理认证头转换
 function extractProxyHeaders(req: Request): Record<string, string> {
   const headers: Record<string, string> = {};
-  for (const header of PROXY_HEADERS) {
-    const value = req.headers[header];
-    if (value) {
-      headers[header] = Array.isArray(value) ? value[0] : value;
+  const baseUrl = getBaseUrl();
+
+  // 如果上游是智谱 AI 等，需要将 x-api-key 转换为 Authorization: Bearer
+  if (baseUrl.includes('bigmodel.cn') || baseUrl.includes('open.bigmodel')) {
+    // 优先使用 x-api-key，其次使用 Authorization
+    const rawHeaders = req.headers as Record<string, string | string[] | undefined>;
+    const xApiKey = rawHeaders['x-api-key'];
+    const authHeader = rawHeaders['authorization'];
+
+    const apiKey = (Array.isArray(xApiKey) ? xApiKey[0] : xApiKey) ||
+      (Array.isArray(authHeader) ? authHeader[0] : authHeader)?.replace?.(/^Bearer\s+/i, '');
+
+    if (apiKey) {
+      headers['authorization'] = `Bearer ${apiKey}`;
+    }
+    // 复制其他 headers
+    for (const header of PROXY_HEADERS) {
+      if (header === 'x-api-key' || header === 'authorization') continue;
+      const value = req.headers[header];
+      if (value) {
+        headers[header] = Array.isArray(value) ? value[0] : value;
+      }
+    }
+  } else {
+    // 标准 Claude API，直接透传
+    for (const header of PROXY_HEADERS) {
+      const value = req.headers[header];
+      if (value) {
+        headers[header] = Array.isArray(value) ? value[0] : value;
+      }
     }
   }
+
   return headers;
 }