ai(rules[AGENTS]) add HEREDOC pattern for multi-line git commits

why: Ensure proper formatting of why/what sections in commit messages.
what:
- Add example using cat <<EOF style for multi-line commits

Author: tony

AGENTS.md

@@ -244,6 +244,18 @@ what:
 - Update GitURL.to_url() to include port if specified
 - Add tests for the new functionality
 ```
+For multi-line commits, use heredoc to preserve formatting:
+```bash
+git commit -m "$(cat <<'EOF'
+feat(Component[method]) add feature description
+
+why: Explanation of the change.
+what:
+- First change
+- Second change
+EOF
+)"
+```
 
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