## Summary
<!-- One sentence describing what changed and why. -->
## Changes
- **What**: <!-- Core functionality added/modified -->
- **Breaking**: <!-- Any breaking changes (if none, remove this line)
-->
- **Dependencies**: <!-- New dependencies (if none, remove this line)
-->
## Review Focus
<!-- Critical design decisions or edge cases that need attention -->
<!-- If this PR fixes an issue, uncomment and update the line below -->
<!-- Fixes #ISSUE_NUMBER -->
## Screenshots (if applicable)
<!-- Add screenshots or video recording to help explain your changes -->
┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10157-feat-website-add-zh-CN-translations-for-homepage-and-secondary-pages-3266d73d3650811f918cc35eca62a4bc)
by [Unito](https://www.unito.io)
---------
Co-authored-by: GitHub Action <action@github.com>
## Summary
Adds the layout shell for the marketing site: SEO head, analytics, nav,
and footer.
## Changes (incremental from #10140)
- BaseLayout.astro: SEO meta (OG/Twitter), GTM (GTM-NP9JM6K7), Vercel
Analytics, ClientRouter, i18n
- SiteNav.vue: Fixed nav with logo, Enterprise/Gallery/About/Careers
links, COMFY CLOUD + COMFY HUB CTAs, mobile hamburger with ARIA
- SiteFooter.vue: Product/Resources/Company/Legal columns, social icons
## Stack (via Graphite)
- #10140 [1/3] Scaffold ← merge first
- **[2/3] Layout Shell** ← this PR
- #10142 [3/3] Homepage Sections
┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10141-feat-add-layout-shell-BaseLayout-SiteNav-SiteFooter-2-3-3266d73d365081aeb2d7e598943a8e17)
by [Unito](https://www.unito.io)
