docs: log github publication channel

[saagpatel]

What

• Marked the public GitHub repo package as the first completed publication channel in docs/demo/publication-log.md.
• Left portfolio site, LinkedIn, email packet, short DM, and video post pending until those human-operated channels are actually posted or sent.
• Added a safe completed-entry example for the GitHub repo package.

Why

The outbound package is now live on master, so the publication log can truthfully record the public GitHub package URL without pretending a social post, email, DM, or portfolio-site publication happened.

How

• Added a GitHub repo package row with the public outbound-share-package URL.
• Added a matching safe entry documenting attachments, links, source draft, follow-up, and safety check.

Testing

• pnpm exec prettier --check docs/demo/publication-log.md
• Publication-log link and package path existence check.
• Sanitized boundary scans for private/company placeholders and stale device-policy examples.
• Stale text scan for fixed test counts, old gap labels, stale deck-preview notes, public PPTX links, hype words, and direct email markers.
• pdfinfo sanity checks for one-pager and deck PDFs.
• sips dimension check for screenshot contact sheet.
• node scripts/ci/check-workstation-preflight.mjs
• node scripts/ci/check-workflow-command-drift.mjs
• node scripts/ci/check-version-parity.mjs
• git diff --check
• Git branch, atomic, generated, large-file, and secrets guards.

Risks

Low. Documentation-only change. This records only the already-public GitHub package URL; other channels remain pending.

Performance impact

None expected. Documentation-only change; no runtime, bundle, API, database, or UI behavior changed.

Lockfile rationale

No lockfiles changed.

Screenshots

Not applicable. Documentation-only change; no UI surface changed.