* fix(ecstore): send valid ping body in remote locker
Build ping requests with a flatbuffer payload so health checks remain compatible with the ping response parser after restart.
* fix(bench): use multi-host warp target during failover
Normalize comma-separated warp host lists in run_object_batch_bench and let four-node failover bench pass BENCH_WARP_HOSTS so rolling restart does not pin load to a single restarting node.
* feat(health): add compat health probes with busy/KMS checks
- Add /health/live liveness probe endpoint
- Add busy protection (429) for readiness probes, gated by RUSTFS_HEALTH_COMPAT_BUSY_CHECK_ENABLE
- Add KMS readiness check for /health/ready, gated by RUSTFS_HEALTH_COMPAT_KMS_READY_CHECK_ENABLE
- Add lock quorum status caching with TTL to reduce RPC pressure
- Consolidate health response building into build_health_response_parts
- Register /health/live in console router and readiness gate
- Remove MinIO references from newly added health code
* fix(health): decouple kms readiness from lock quorum