fix: correct max_keys field in list_object_versions response (#1576)

Signed-off-by: 安正超 <anzhengchao@gmail.com>
Co-authored-by: loverustfs <hello@rustfs.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

rustfs/src/storage/ecfs.rs

@@ -3725,8 +3725,6 @@ impl S3 for FS {
             })
             .collect();
 
-        let key_count = objects.len() as i32;
-
         let common_prefixes = object_infos
             .prefixes
             .into_iter()
@@ -3753,7 +3751,9 @@ impl S3 for FS {
 
         let output = ListObjectVersionsOutput {
             is_truncated: Some(object_infos.is_truncated),
-            max_keys: Some(key_count),
+            // max_keys should be the requested maximum number of keys, not the actual count returned
+            // Per AWS S3 API spec, this field represents the maximum number of keys that can be returned in the response
+            max_keys: Some(max_keys),
             delimiter,
             name: Some(bucket),
             prefix: Some(prefix),