feat: Convert API to use client/server split for client package

• feat: Add API REST clients for the server

Assisted-by: Claude Sonnet-4.6

• fix: Update the generic skill to account for variable package dirs

When the skill was generated in the FoundationDB, it had made the assumption that there will always be an entity package with a machine name in the output clients and parameter classes. Instead, it should be flexible and capture whatever the input was and reflect it in the output.

Assisted-by: Claude Sonnet-4.6

• feat: Convert API to use client/server split for client package

Initial switchover for code to use client extension and server API jar. This split will allow us in the future to release a client package for APIs to consume in a way that is consistent with the server usage and models. This is a part of the effort to replace the efservices common SDK when there is an available Java project. While not included in commons, this is one of our simplest APIs and presents a good POC for conversion and clients.