Netflix/dgs-framework ? reverse-engineered prompt

Build me a Spring Boot GraphQL framework that makes it really easy to define GraphQL APIs in Kotlin and Java.

I want the main experience to feel simple and annotation based, with good support for schema driven development, code generation from the schema, and a clean way to write query tests as normal unit tests. It should also support GraphQL federation, subscriptions over WebSockets and SSE, file uploads, security integration, and solid error handling.

Please include a few working example apps so I can see the different styles in action, plus starter and test modules that show the intended usage. If you need to check current Spring Boot or GraphQL docs while wiring things up, go ahead and do that. Make the setup polished enough that someone can clone it, run the tests, and understand how to start building a real GraphQL service with it.