Add a contributor showcase to the Community page

[imbajin]

Background

The refreshed Community page restores the core ways to learn, connect, and contribute. A visual contributor showcase should be designed and delivered separately so the OINK migration stays focused.

Scope

• Add a bilingual contributor avatar/list section to the Community page.
• Link each visible contributor to their public profile and provide accessible names and image fallbacks.
• Define the included Apache HugeGraph repositories, ordering, update cadence, and a reproducible data-generation process.
• Keep generated data reviewable in the repository; do not call the GitHub API from visitors' browsers.
• Lazy-load avatars and verify CSP, privacy, responsive layout, dark mode, and empty/error states.

Acceptance criteria

• English and Chinese Community pages present the same contributor set.
• The list is keyboard-accessible and usable without JavaScript.
• Contributor data can be refreshed with a documented command and produces deterministic output.
• CI validates generated data and broken profile/image links.

Follow-up to #466.