test

                  << " sgid=" << sgid << " sid_gid=" << sid_gid

                  << " data_size=" << data.size() << std::endl;

        // Dedicated session client — no contention with domain fetches

        std::unique_lock<std::timed_mutex> lock(session_client_mutex_, std::chrono::seconds(2));

        if (!lock.owns_lock())

            throw AuthBackendError("cluster busy — session push timeout");

        // Dedicated session client — retry loop with short lock attempts

        for (int attempt = 0; attempt < 5; ++attempt) {

            std::unique_lock<std::timed_mutex> lock(session_client_mutex_, std::chrono::milliseconds(200));

            if (!lock.owns_lock()) {

                std::cerr << "[CLUSTER-SESSION] pushSession: lock attempt " << attempt + 1

                          << "/5 failed, retrying..." << std::endl;

                std::this_thread::sleep_for(std::chrono::milliseconds(100));

                continue;

            }

            try {

                session_client_->store(sgid, data.data(), data.size());

                session_client_->store(sid_gid, data.data(), data.size());

            } catch (const std::exception &e) {

            std::cerr << "[CLUSTER-SESSION] pushSession: store FAILED: " << e.what() << std::endl;

                std::cerr << "[CLUSTER-SESSION] pushSession: store attempt " << attempt + 1

                          << "/5 FAILED: " << e.what() << std::endl;

                if (attempt < 4) {

                    std::this_thread::sleep_for(std::chrono::milliseconds(200));

                    continue;

                }

                throw;

            }

        // Immediately verify local shard exists

            // Verify and return on success

            try {

                auto verify = session_client_->retrieve(sid_gid);

                std::cerr << "[CLUSTER-SESSION] pushSession: stored OK, verify=" << verify.size() << " bytes" << std::endl;

            } catch (const std::exception &e) {

                std::cerr << "[CLUSTER-SESSION] pushSession: stored but verify failed: " << e.what() << std::endl;

            }

            return;

        }

        throw AuthBackendError("cluster busy — session push timeout after 5 retries");

    }

    void Cluster::queuePush(const SessionData &sess) {