Preserve global typography and metadata in MJML exports

packages/email-renderer/src/email.ts

@@ -140,6 +140,8 @@ export async function renderEmail(
     direction: options.direction ?? "ltr",
     countdownImageUrl: options.countdownImageUrl,
     brandLinkColor: String(source.root.props.linkColor ?? "#2563eb"),
+    emailSubject: String(source.meta.subject),
+    emailPreheader: String(source.meta.preheader ?? ""),
     rootBlockIds: Object.values(source.root.slots).flat().map(node => node.id),
   };
   const [htmlResult, textResult, mjmlResult] = await Promise.all([