Rollback: prepare exact pre-header Netlify artifact

[daliu]

Prepares and previews the exact website artifact that was live before the #457 header release. Keep this PR in draft and do not merge while production is healthy.

Refs #457

Current preparation:

• Branch base: current main documentation merge a70545760510ed5e6575919eac9b8111e97f927f.
• Expected production first parent: a70545760510ed5e6575919eac9b8111e97f927f.
• Rollback source: e86a0f702cff6495f50630c5de3337290db8b8cb.
• Source tree: 149627cdf65e1ebd34f6586200469ce330dca358.
• Exact preview: Netlify deploy 6a61cf4b22a1580008821ba2 at control head 2f2bbf1abab7f303c09ca27606966cee8b3938cc.
• Verified artifact: 60 files, SHA-256 72d690a7d1faa5b707fc10ce3c50387d31f7c4745df4d21453c90d4a2a84ebe4, bundles main.58ede287.js / main.cdd8bda4.css.
• The dedicated rollback source ref remains available; published production deploy 6a61c544171ea80008307623 is unchanged.

Before an emergency merge, confirm production is unhealthy, confirm main still equals the expected parent, require current-head checks and the exact Netlify preview to pass, and merge with a merge commit only. If main has advanced, refresh this draft and its expected parent first; this approval and preview then expire.

Officer impact: none while production is healthy. In an approved incident, this draft restores the prior public website through the reviewed Git/Netlify exact-artifact path.

Officer documentation: docs/officers/PUBLISH_AND_CHECK.md and OPERATIONS_RUNBOOK.md describe the rollback decision and proof requirements; no new officer action is introduced here.

Deployment evidence: focused exact-release tests pass 12/12; exact-head GitHub Actions runs 29991306409 and 29991961922 passed all five jobs; Netlify preview 6a61cf4b22a1580008821ba2 and its public marker match the pinned former-live artifact. Firebase and outside providers are unchanged.

[netlify]

✅ Deploy Preview for luminous-fox-7c393f ready!

Name	Link
🔨 Latest commit	2f2bbf1
🔍 Latest deploy log	https://app.netlify.com/projects/luminous-fox-7c393f/deploys/6a61cf4b22a1580008821ba2
😎 Deploy Preview	https://deploy-preview-462--luminous-fox-7c393f.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.

[daliu]

Rollback readiness refreshed after the production merge:

• Branch is based on production merge 4f67e6cafb975a3f985fefc67f094b3a37526702, and the rollback manifest expects that exact first parent.
• Current-head CI is green across all five jobs.
• Netlify preview deploy 6a61c6451d1539000858463e is ready. Marker control 075b9a82f67c3c53d30b25e5cab13f031985cd4d pins source e86a0f702cff6495f50630c5de3337290db8b8cb, tree 149627cdf65e1ebd34f6586200469ce330dca358, 60 files, and digest 72d690a7d1faa5b707fc10ce3c50387d31f7c4745df4d21453c90d4a2a84ebe4.
• Preview bundles are main.58ede287.js and main.cdd8bda4.css, exactly matching the former live deployment.

This PR is returned to draft. Do not merge while production is healthy. If a future rollback is needed after any later main change, rebase it again and re-pin/reverify its exact parent before merging.

[daliu]

Temporarily closing and reopening this draft at the same exact head 2f2bbf1abab7f303c09ca27606966cee8b3938cc because GitHub/Netlify have not emitted current-head checks after the force update. No code or production state is changing.

[daliu]

Final refreshed rollback evidence for current healthy production:

• Draft head 2f2bbf1abab7f303c09ca27606966cee8b3938cc has sole parent/current main a70545760510ed5e6575919eac9b8111e97f927f.
• Manifest expectedProductionParent matches that exact current main.
• Focused release-policy tests pass 12/12; two current-head CI runs (29991306409, 29991961922) passed all five jobs.
• Netlify preview 6a61cf4b22a1580008821ba2 is ready and its public marker matches source e86a0f702cff6495f50630c5de3337290db8b8cb, tree 149627cdf65e1ebd34f6586200469ce330dca358, 60 files, and digest 72d690a7d1faa5b707fc10ce3c50387d31f7c4745df4d21453c90d4a2a84ebe4.
• Preview bundles main.58ede287.js / main.cdd8bda4.css match the former live site.
• Production remains healthy at deploy 6a61c544171ea80008307623; documentation merge attempt 6a61d10d69aef30007454a71 is error/unpublished.

Keep this PR draft. If main advances, refresh and reverify it before any emergency merge.