add AGENTS.md

Add AGENTS.md to allow AI assistants to be more effective, especially
the Code Review Bot.

Note: do not create .github/copilot-instructions.md as it will prevent
current version of Copilot CLI from reading AGENTS.md at all.

Signed-off-by: Tuomo Tanskanen <[email protected]>

Author: tuminoid

.gitignore

@@ -74,3 +74,6 @@ go.work.sum
 
 # e2e result junit xml files
 junit.e2e_suite.*.xml
+
+# ai stuff
+.claude