Add text file for coding LLMs with high-level nwaku info and style guide advice (#3624)

* add CLAUDE.md first version

* extract style guide advice

* use AGENTS.md instead of CLAUDE.md for neutrality

* chore: update AGENTS.md w.r.t. master developments

* Apply suggestions from code review

Co-authored-by: Ivan FB <[email protected]>

* remove project tree from AGENTS.md; minor editx

* Apply suggestions from code review

Co-authored-by: NagyZoltanPeter <[email protected]>

---------

Co-authored-by: Ivan FB <[email protected]>
Co-authored-by: NagyZoltanPeter <[email protected]>

Author: 3 people