Remove AGENTS.md from repo and ignore local copies.

Drop Codex/agent notes from version control; keep AGENTS.md as a local-only file via .gitignore.

Author: phaupt

.gitignore

@@ -22,4 +22,5 @@ node_modules
 
 # AI assistant / editor local tooling (never commit)
 .claude/
-.cursor/
+.cursor/
+AGENTS.md