feat: refresh website design and community pages

[dengliming]

The public pages use inconsistent layouts and duplicated locale-specific content. This refresh gives the English and Chinese sites a shared visual style, clearer navigation, and a consistent footer across page types.

Changes

• Refresh typography, spacing, responsive layouts, dark mode, navigation, and language switching. Match the existing Ask AI widget to the site palette and keep the search keyboard shortcut available.
• Rework the homepage with switchable stacked architecture diagrams, including the diagram from the ShenYu README with source attribution, and restore the eight-image Admin gallery.
• Present users in compact scrolling logo rows that pause independently on hover, with instructions for submitting a company. Replace duplicated team tables with localized cards backed by shared member data.
• Refresh blog summaries, archives, tag pills, news, and release listings while retaining Docusaurus pagination and article routes.
• Rebuild the documentation and download landing pages with version selection, client and deployment resources, Docker Hub links, and signature/checksum verification guidance.

Validation

• English and Chinese production builds passed after incorporating upstream main at 4de8adaf74. The subsequent Ask AI palette adjustment was checked in the browser in both themes.
• Repository-wide Markdown lint passed using the same markdownlint-cli@0.25.0 version and configuration as CI; git diff --check passed.
• Checked the homepage, documentation, download, team, users, events, news, blog, and tag routes in both locales, including shared footer and Ask AI loading.
• Checked mobile layouts, dark mode, keyboard interactions, locale switching, architecture/gallery controls, and independent logo-row hover behavior.

The build still reports existing historical Markdown link warnings. Ask AI launcher and modal behavior were verified; answer generation could not be verified because the provider rejected the automated browser query through its bot protection.