Simplify current AGENTS.md

[jabrena]

• https://github.com/jabrena/cursor-rules-java/blob/main/AGENTS.md

[jabrena]

https://agents.md/

[jabrena]

https://github.blog/ai-and-ml/github-copilot/how-to-write-a-great-agents-md-lessons-from-over-2500-repositories/

[jabrena]

#435