feat(ecstore): type internode client-acquisition failures for quorum buckets (#6619)

* feat(ecstore): type internode client-acquisition failures for stable quorum buckets

Backlog#1845 step 3, first typed family. The largest other(format!) message family in ecstore was 'can not get client, err: {detail}' (~50 production sites): every internode RPC that fails to acquire a client wrapped the dial/auth error with per-peer detail into DiskError::other / StorageError::other, whose Io equality compares the rendered message. N disks failing for this same cause therefore counted as N distinct errors in reduce_errs, starving quorum aggregation, and remote_disk call sites double-wrapped the message on top of get_client's own wrap.

Introduce DiskError::RemoteClientUnavailable(String) (wire code 0x2B) and its StorageError twin (StorageErrorCode 0x54): equality and hashing use the wire code alone, so same-cause failures land in one quorum bucket regardless of per-peer detail, while Display keeps the detail so substring classifiers (network needles, heal recoverability) keep reading it unchanged. Wire encoding carries the rendered detail in error_info and decode restores the typed variant; old peers fall back to the legacy string form gracefully.

Call sites: remote_disk get_client/get_bulk_client/offline-bypass/recovery-probe now construct the typed variant and the ~60 redundant double-wrap map_errs are gone; peer_rest_client's three client getters and offline gates, peer_s3_client, and admin_server_info follow. The tier-config-reload connection classifier's anchored 'can not get client' substring check becomes a typed match on the variant (the string form is retired and now classifies as Terminal, pinned by test).

Ref rustfs/backlog#1845

* chore(ci): refresh error other ratchet baseline

* fix(ecstore): classify typed client network failures

crates/ecstore/src/diagnostics/admin_server_info.rs

@@ -148,7 +148,7 @@ async fn is_server_resolvable(endpoint: &Endpoint) -> Result<()> {
 
         let mut client = node_service_time_out_client(&addr, TonicInterceptor::Signature(gen_tonic_signature_interceptor()))
             .await
-            .map_err(|err| Error::other(format!("can not get client, err: {err}")))?;
+            .map_err(|err| Error::RemoteClientUnavailable(err.to_string()))?;
 
         let request = Request::new(PingRequest {
             version: 1,