chore: import upstream snapshot with attribution

apps/sim/app/(landing)/layout.tsx

@@ -0,0 +1,47 @@
+import type { ReactNode } from 'react'
+import { Suspense } from 'react'
+import type { Metadata } from 'next'
+import Script from 'next/script'
+import { isHosted } from '@/lib/core/config/env-flags'
+import { SITE_URL } from '@/lib/core/utils/urls'
+import { LandingShell } from '@/app/(landing)/components'
+import { HubspotPageViewTracker } from '@/app/(landing)/hubspot-page-view-tracker'
+
+const HUBSPOT_SCRIPT_SRC = 'https://js-na2.hs-scripts.com/246720681.js' as const
+
+/**
+ * Route-group layout for the entire landing family - the home page, platform and
+ * solutions pages, pricing, legal, and the marketing subroutes (blog, models,
+ * integrations, partners).
+ *
+ * It renders the shared chrome **once** via {@link LandingShell} (the `light`
+ * token layer + scroll port, the skip link, the {@link Navbar} with
+ * build/revalidate-time GitHub stars, the site-wide JSON-LD, and the
+ * {@link Footer}). Because layouts persist across client navigations, the navbar
+ * and footer mount once and are never torn down when moving between landing
+ * pages - no remount, no refetch, no flash.
+ *
+ * Each page supplies only its `<main id='main-content'>` content (and any
+ * page-specific metadata / JSON-LD). `metadataBase` here lets pages express
+ * relative canonical/OG URLs; every other metadata field stays per-page.
+ */
+export const metadata: Metadata = {
+  metadataBase: new URL(SITE_URL),
+}
+
+export default function LandingLayout({ children }: { children: ReactNode }) {
+  return (
+    <LandingShell>
+      {children}
+      {/* HubSpot tracking — hosted only */}
+      {isHosted && (
+        <>
+          <Script id='hs-script-loader' src={HUBSPOT_SCRIPT_SRC} strategy='afterInteractive' />
+          <Suspense fallback={null}>
+            <HubspotPageViewTracker />
+          </Suspense>
+        </>
+      )}
+    </LandingShell>
+  )
+}