I want EliasDB's graph Manager to expose a stateful node-key iterator for scanning the keys of stored nodes…

I want EliasDB's graph Manager to expose a stateful node-key iterator for scanning the keys of stored nodes…: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). Given a manager with nodes key=123, kind=mykind , key=789, kind=mykind , and key=456, kind=mykind2 stored…