remove authorship attribution rule from AGENTS.md

Co-Authored-By: Claude (Opus 4.7) <noreply@anthropic.com>

Author: silverwind

AGENTS.md

@@ -1,4 +1,3 @@
 - Use `make` to run development tasks
 - Before committing files, ensure that related `lint` tasks in `make` pass
 - Never force-push to pull request branches
-- Always start issue and pull request comments with an authorship attribution