Avoid exclamation marks inside Bash heredocs

Never pipe file content containing '!' through Bash heredocs (python3 - <<EOF, cat <<EOF): the harness escapes bangs into backslash-bang, silently corrupting C++ negations, org text and search strings.

Why: Bit five separate times in one session: broken C++ (\!result), corrupted org prose, and silent .replace() mismatches whose search strings no longer matched the clean file.

How to apply: Use the Write or Edit tools for content with exclamation marks; if a heredoc is unavoidable, grep the written file for backslash-bang immediately and sed it clean.