feat: implement native ARM64 Docker builds with CDN support (#791)

* feat: implement native ARM64 Docker builds with CDN support

- Replace QEMU emulation with native ARM64/AMD64 runners (linux-arm64-8-core, linux-x64-8-core)
- Fix manifest creation with proper error handling and image existence checks
- Add CDN video support with getVideoUrl function and Video component
- Update all docs MDX files to use Video component instead of raw video tags
- Update GitHub Actions workflow to use architecture-specific builds
- Remove QEMU setup to eliminate emulation timeout issues
- Maintain multi-arch Docker image support through manifests

* Update .github/workflows/build.yml

Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>

---------

Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>

apps/docs/lib/utils.ts

@@ -7,3 +7,15 @@ import { twMerge } from 'tailwind-merge'
 export function cn(...inputs: ClassValue[]) {
   return twMerge(clsx(inputs))
 }
+
+/**
+ * Get the full URL for a video asset stored in Vercel Blob
+ */
+export function getVideoUrl(filename: string) {
+  const baseUrl = process.env.NEXT_PUBLIC_BLOB_BASE_URL
+  if (!baseUrl) {
+    console.warn('NEXT_PUBLIC_BLOB_BASE_URL not configured, falling back to local path')
+    return `/${filename}`
+  }
+  return `${baseUrl}/${filename}`
+}