chore(web): remove heavyweight homepage dependencies

[SarthakWade]

Summary

• replace WebGL decorations and Recharts with server-rendered HTML and CSS
• replace the pixel-bound GitHub screenshot with a repository-owned semantic browser demo
• remove unused UI variants, assets, and dependencies while enforcing the bundle boundary in web lint

Validation

• pnpm --filter @headless/web lint
• pnpm --filter @headless/web build
• pnpm test
• pnpm test:runtime
• pnpm build
• pnpm test:e2e:linux
• desktop and narrow viewport render review

Closes #51

[yashranaway]

Reviewed the dependency cleanup, server-rendered chart replacements, semantic demo, CSS, and backlog update. Verified lint/build, the merged lucide 1.33 lockfile, and rendered Chromium behavior with zero console or network failures. The built static JS fell from 1,616,781 to 601,199 bytes.