feat: add a new TLS client with browser fingerprinting and implement Codex API authentication.

backend/internal/client/tls.go

@@ -588,6 +588,15 @@ func (c *TLSClient) GetFingerprintInfo() string {
 	return fmt.Sprintf("%s/%s %s (%s)", typeName, fp.Browser, fp.Version, fp.Platform)
 }
 
+// GetHeadersInfo 获取指纹对应的 User-Agent、sec-ch-ua、sec-ch-ua-platform
+// 供 codex_api 等外部模块使用，确保 headers 与 TLS 指纹一致
+func (c *TLSClient) GetHeadersInfo() (userAgent, secChUa, secChPlatform string) {
+	userAgent = c.userAgent
+	secChUa = c.generateSecChUa()
+	secChPlatform = c.getPlatformHeader()
+	return
+}
+
 // Close 关闭客户端
 func (c *TLSClient) Close() {
 	if c.azureSession != nil {