Port paperback interior build/QA alongside the eBook path, with gray
asset staging, footer-safe bottom margins, and updated author harness
docs. Includes manuscript polish and rebuilt eBook/print PDFs.
Clarify harness wording and CI/team paths across chapters, update
assets and hook templates, expand the GitHub Actions example, and
ship a fresh dist/codex-harness.pdf (98 pages, QA clean).