test

                    }

                }

                // Verify local store is writable

                bool store_ok = true;

                if (store_) {

                    try {

                        // Write and remove a sentinel block to test I/O

                        const uint64_t sentinel_gid = 0;

                        const uint32_t sentinel_idx = UINT32_MAX;

                        uint8_t probe = 0x01;

                        store_ok = store_->store(sentinel_gid, sentinel_idx, &probe, 1);

                        if (store_ok)

                            store_->remove_group(sentinel_gid);

                    } catch (...) {

                        store_ok = false;

                    }

                    if (!store_ok && !critical_) {

                        std::cerr << "Cluster: CRITICAL — local store not writable"

                                  << std::endl;

                    }

                }

                bool was_critical = critical_;

                if (health.nodes_online >= n) {

                if (!store_ok) {

                    degraded_ = true;

                    critical_ = true;

                } else if (health.nodes_online >= n) {

                    if (degraded_) {

                        std::cerr << "Cluster: recovered — all "

                                  << health.nodes_online << "/" << n