ephemeral-tmp-pattern-for-zero-drift-github-sync

To sync live skills to a GitHub backup repo without creating persistent local duplicity: clone to /tmp/helix-sync, rsync from live skills path, commit, push, then rm -rf /tmp/helix-sync. The temp dir is cleaned immediately after push — zero persistent intermediate copy, zero drift surface. This is the correct one-shot sync pattern for milestone preservation without violating the two-source model.