[MAINT]: net-new agentic sync machinery whose job is just to keep the generated code in sync.

### Describe the need

Internal tracking issue https://devdiv.visualstudio.com/DevDiv/_workitems/edit/2934353 .

### SDK Version

0.3.0-java-preview.1

### Relevant log output

```shell

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### Code of Conduct

- [x] I agree to follow this project's Code of Conduct