fix(ecstore): handle free-version migration races

crates/ecstore/src/set_disk/mod.rs

@@ -249,6 +249,7 @@ async fn inspect_decommission_tier_free_version_target(
     {
         matching_count += 1;
         let existing = existing.into_fileinfo(bucket, object, true)?;
+        existing.validate_for_metadata_read()?;
         if !existing.tier_free_version() || !crate::store::tiered_data_movement_source_matches(source, &existing)? {
             all_matching_versions_equivalent = false;
         }