livy:What are the plans for the later stage

What are the plans for the later stage, whether they support more engines, whether it is better for tenants, isolation, and context support。
What are the advantages and differences compared to Apache Linkis

This issue asks for Livy's later-stage plans rather than identifying a specific file, test, or entry point. First review the project's roadmap and existing discussions around additional engines, tenant support, isolation, context support, and differences from Apache Linkis; it is done only when maintainers define an actionable scope.

Written by the indexing model from the issue text.