docs site: homepage hero cover is a 406 KB PNG served at ~1024 px

[os-zhuang]

One-liner

apps/docs/public/hero-cover-dark.png is a 2400×1200 PNG, 406 KB, displayed at ~1024 px as the homepage video poster (added in #12218). It is the largest element above the fold, so it is the LCP candidate.

Measured

$ ls -la apps/docs/public/hero-cover-dark.png
406703 bytes
$ file apps/docs/public/hero-cover-dark.png
PNG image data, 2400 x 1200, 8-bit/color RGB

Expected

Either

• serve it through next/image (automatic resize + WebP/AVIF negotiation), which is the idiomatic fix in this app but introduces the first next/image usage on the site — check it works on the Vercel deployment before claiming it; or
• ship a pre-encoded WebP alongside and reference that, keeping the PNG only where the README needs it.

Expect ~80% off the transfer either way. Keep the poster visually identical — it is the same cover the README uses, and the two should not drift.

Acceptance

• homepage poster transfers under ~100 KB on a cold load
• the rendered poster is visually unchanged at 1×, and sharp at 2×
• docs/screenshots/hero-cover-dark.png (README's copy) still resolves

Source

Found in an SEO review of the docs site (apps/docs) run on 2026-08-25, measured against the local dev server and against production. The canonical origin is https://objectstack.ai — maintainer ruling recorded in #10659:

这个仓的文档站规范 URL 是 https://objectstack.ai

[os-zhuang]

Unblocked: PR #12218 merged to main at 2026-08-25T14:56:33Z as eeec62a98, so apps/docs/public/hero-cover-dark.png and its reference in apps/docs/app/[lang]/page.tsx are now on main and this card has a real base to work against.

Still held one more round — not by #12218 any more, but by a hot file: #12239 (homepage title/description) edits apps/docs/app/[lang]/page.tsx too, and it is the higher-priority card (p1 keyword work vs p2 weight). One of the two goes per round. Known trap to carry into whichever goes second: the poster reference and the page metadata live in the same file, so the second card must rebase rather than assume its base still matches what it read.