feat(home): polish AgentsKit ecosystem experience

[EmersonBraun]

Summary

• Refine the AgentsKit home with a restrained liquid cursor gradient, a dark Apple-inspired visual system, and quieter ecosystem sections.
• Align the global ecosystem navigation, showcase tour, footer, and selected-repository GitHub link across the six products; keep the chat closed by default.
• Improve responsive and reduced-motion behavior, including hiding the flow lines on mobile.
• Synchronize generated ecosystem, Doc Bridge, README freshness, and provider-count artifacts.

Validation

• pnpm check:quality-gates — all 42 gates passed.
• Push hook lint and build — passed for all 43 packages; docs build generated 1,209 pages.
• Playwright browser checks on desktop, tablet, and mobile; screenshots: /tmp/agentskit-home-ui-desktop-final.png, /tmp/agentskit-home-ui-mobile-final.png.
• git diff --check — passed.

The UI screenshots and browser review are available for final human visual approval.

[github-actions]

Lighthouse

URL	Performance	Accessibility	Best practices	SEO
http://127.0.0.1:3000/	53	99	96	100
http://127.0.0.1:3000/docs	71	100	96	100
http://127.0.0.1:3000/docs/get-started/getting-started/quickstart	74	100	96	100
http://127.0.0.1:3000/stack	90	100	96	100
http://127.0.0.1:3000/showcase	93	100	96	100

Run by .github/workflows/lighthouse.yml.

[github-actions]

Lighthouse

URL	Performance	Accessibility	Best practices	SEO
http://127.0.0.1:3000/	64	99	96	100
http://127.0.0.1:3000/docs	68	100	96	100
http://127.0.0.1:3000/docs/get-started/getting-started/quickstart	68	100	96	100
http://127.0.0.1:3000/stack	92	100	96	100
http://127.0.0.1:3000/showcase	91	100	96	100

Run by .github/workflows/lighthouse.yml.

[github-actions]

Lighthouse

URL	Performance	Accessibility	Best practices	SEO
http://127.0.0.1:3000/	59	99	96	100
http://127.0.0.1:3000/docs	74	100	96	100
http://127.0.0.1:3000/docs/get-started/getting-started/quickstart	73	100	96	100
http://127.0.0.1:3000/stack	90	100	96	100
http://127.0.0.1:3000/showcase	92	100	96	100

Run by .github/workflows/lighthouse.yml.