Document signals.forwardfuture.ai redirect

[mberman84]

Summary

• add source/runbook for the Vercel redirect-only project serving signals.forwardfuture.ai
• document that the legacy .ai host redirects to signals.forwardfuture.com

Verification

• node --check loop-library/site/script.js
• node loop-library/scripts/check.mjs
• npm --prefix loop-library/worker run check
• python3 -m json.tool loop-library/site/.herenow/data.json >/dev/null
• python3 -m json.tool loop-library/site/.herenow/proxy.json >/dev/null
• python3 -m json.tool loop-library/scripts/seo-geo-query-benchmark.json >/dev/null
• git diff --check
• curl -IL https://signals.forwardfuture.ai/loop-library/?x=1