fix: harden GET object performance paths (#4271)

* fix: harden GET object performance paths

* fix: satisfy GET multipart layer guard

* fix: keep v1 list markers S3 compatible

* perf: tighten GET direct-memory decision

* ci: isolate s3tests from scanner workload

* refactor: simplify get object body lifecycle

* fix: satisfy get object clippy

crates/ecstore/src/set_disk/read.rs

@@ -371,6 +371,9 @@ impl MetadataQuorumAccumulator {
     /// Check if a versioned request can early-stop because the requested
     /// version_id has reached quorum across disks.
     fn version_early_stop_decision(&self) -> Option<MetadataEarlyStopDecision> {
+        if !self.allow_early_stop {
+            return None;
+        }
         if self.requested_version_id.is_empty() {
             return None;
         }
@@ -4388,6 +4391,18 @@ mod tests {
         MetadataQuorumAccumulator::new(4, 2, true).with_requested_version_id(requested_version_id)
     }
 
+    #[test]
+    fn version_early_stop_respects_disabled_accumulator() {
+        let vid = Uuid::new_v4();
+        let mut accumulator = MetadataQuorumAccumulator::new(4, 2, false).with_requested_version_id(&vid.to_string());
+
+        accumulator.observe_file_info(&version_early_stop_candidate("object", 1, vid));
+        accumulator.observe_file_info(&version_early_stop_candidate("object", 2, vid));
+
+        assert!(accumulator.version_early_stop_decision().is_none());
+        assert_eq!(accumulator.matching_version_votes, 2);
+    }
+
     #[test]
     fn version_early_stop_hits_quorum_with_matching_versions() {
         let vid = Uuid::new_v4();