Add AGENTS.md to the repo

[filiperochalopes]

OpenConceptLab/oclapi2#808 (comment)

We’re living in a new era of programming, and the efficiency of AI models for bug-fixing, code maintenance, and even implementing features through agents depends on minimizing waste and following consistent standards.
That’s why having an AGENTS.md is important — to ensure we’re not introducing low-quality code and that agents operate with predictable structure and context.

You can read more about it here: https://agents.md/