gh issue create with heredoc body breaks on apostrophes

Bash command substitution $(cat <<'EOF'...EOF) tracks single quotes globally even when the heredoc is quoted (<<'EOF'), so apostrophes inside the body (user's, isn't) cause unmatched-quote errors. Reliable fix: write the body to a temp file and use gh issue create --body-file /tmp/issue.md. Works regardless of body content; also makes it easy to iterate on the body in an editor.