during rename, we delete old key and create a new one in parallel, which affects transaction atomicity

we run next cb in parallel on 2 shards

```
void Renamer::FinalizeRename() {
auto cb = [this](Transaction* t, EngineShard* shard) {
const ShardId shard_id = shard->shard_id();

if (!do_copy_ && shard_id == src_sid_) {
return DelSrc(t, shard);
}

if (shard_id == dest_sid_) {
return DeserializeDest(t, shard);
}

return OpStatus::OK;
};

transaction_->Execute(std::move(cb), true);
}
```
Consider next flow

DelSrc() -> success
DeserializeDest(t, shard); -> ERROR
but the source is already deleted, so we lost the data

Start at Renamer::FinalizeRename and trace the transaction_->Execute callback through DelSrc and DeserializeDest on the source and destination shards. Reproduce or reason through a successful source deletion followed by destination failure, then verify that a failed rename does not leave the source data lost and that the operation remains atomic.

Written by the indexing model from the issue text.