fix(ecstore): send valid ping body in remote locker (#3112)

* 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

crates/ecstore/src/rpc/remote_disk.rs

@@ -450,7 +450,7 @@ impl RemoteDisk {
 
     async fn mark_faulty_and_evict(&self, reason: &'static str) {
         let previous_state = self.runtime_state();
-        let became_offline = self.mark_suspect_or_offline(reason);
+        let transitioned_to_offline = self.mark_suspect_or_offline(reason);
         let state = self.runtime_state();
 
         if state != previous_state {
@@ -461,7 +461,7 @@ impl RemoteDisk {
                 "reason" => reason.to_string()
             )
             .increment(1);
-            if became_offline || state == RuntimeDriveHealthState::Offline {
+            if transitioned_to_offline {
                 warn!(
                     "Remote disk marked faulty after timeout: endpoint={}, addr={}, reason={}",
                     self.endpoint, self.addr, reason