[chore] Add AGENTS.md file

[mx-psi]

Description

Adds AGENTS.md file. The intent of this file is to:

1. Make sure there is a human in the loop when creating a PR or posting issue comments.
2. Make sure that commits created primarily by an agent are easily identifiable by reviewers

This is heavily inspired on the Open Policy Agent AGENTS.md file and the Fedora AI-assisted contributions policy.

This only affects agents that are compliant with the AGENTS.md file (see https://agents.md for list of tools that support it), as well as Claude Code using this workaround.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.84%. Comparing base (97f66a9) to head (3d0a965).
⚠️ Report is 9 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #14462   +/-   ##
=======================================
  Coverage   91.83%   91.84%           
=======================================
  Files         677      677           
  Lines       42679    42680    +1     
=======================================
+ Hits        39195    39200    +5     
+ Misses       2427     2425    -2     
+ Partials     1057     1055    -2     

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[braydonk]

Not a note on the PR contents, but the PR description appears to have an important typo where point 2 is cut off:

Make sure that commits created primarily by an agent are

[mx-psi]

Not a note on the PR contents, but the PR description appears to have an important typo where point 2 is cut off:

Make sure that commits created primarily by an agent are

Apologies, I was too quick to click the "Mark as ready for review" button. The intent was to say that these commits are easily identifiable.

[mx-psi]

I am going to merge this so we can try it out, we can always revert if there are issues without end-user impact