Move retirement copy to its own page

[cdilga]

Summary

• restore the homepage content to its pre-banner state
• move the retirement and migration explanation to a dedicated /retirement page
• rewrite the retirement copy so it states the actual Hugging Face / offline / ComfyUI plan without internal infra jargon

Verification

• ran npm run build
• smoke tested deploy/ with npx vercel@latest dev deploy --listen 4310 --yes
• confirmed / shows the original homepage FAQ flow and /retirement shows the new retirement page

Notes

• this PR is intentionally left as draft so the preview can be checked before any merge
• no production deploy was triggered from this branch