chore: add AGENTS.md file

[amanabiy]

Issue #, if available:

Description of changes:
Adds AGENTS.md file, a guide

related: X2NaAdxtpFej 0w2zAaLmmgWn

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.90%. Comparing base (b6d9bd6) to head (9ab365d).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #210 +/- ##
=======================================
Coverage 98.90% 98.90% =======================================
Files 44 44 Lines 1185 1185 Branches 318 318 =======================================
Hits 1172 1172 - Misses 12 13 +1 + Partials 1 0 -1 

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