Refresh tunnel actions promptly and clarify Feishu OIDC setup

backend/internal/service/openvpn/oidc.go

@@ -104,7 +104,7 @@ func prepareOIDC(t *model.Tunnel, cfg map[string]interface{}) error {
 		cfg["oidc_client_secret"] = old["oidc_client_secret"]
 	}
 	if service.Str(cfg, "oidc_client_secret") == "" {
-		return fmt.Errorf("oidc_client_secret 必填；请在飞书应用凭据中复制 Client Secret")
+		return fmt.Errorf("oidc_client_secret 必填；请从 OIDC 发行者对应的客户端凭据中复制 Client Secret")
 	}
 	for _, key := range []string{"oidc_http_secret", "oidc_management_password"} {
 		cfg[key] = old[key] // internal secrets are never supplied by the API caller