fix(email-renderer): preserve marketing images across output formats

packages/email-renderer/src/email.ts

@@ -81,7 +81,7 @@ const head = (document: BlockDocument, body: string, direction: "ltr" | "rtl") =
 };
 const ampHead = (document: BlockDocument, body: string, direction: "ltr" | "rtl") => {
   const props = document.root.props as Record<string, unknown>;
-  const css = `body{margin:0;color:${props.textColor ?? "#111827"};font-family:${props.fontFamily ?? "Arial, sans-serif"}}a{color:${props.linkColor ?? "#2563eb"}}.email-bg{background:${props.background ?? "#f3f4f6"}}.email-body{max-width:${props.width ?? "600"}px;width:100%;background:${props.contentBackground ?? "#ffffff"}}`;
+  const css = `.marketing-image img{object-fit:contain}body{margin:0;color:${props.textColor ?? "#111827"};font-family:${props.fontFamily ?? "Arial, sans-serif"}}a{color:${props.linkColor ?? "#2563eb"}}.email-bg{background:${props.background ?? "#f3f4f6"}}.email-body{max-width:${props.width ?? "600"}px;width:100%;background:${props.contentBackground ?? "#ffffff"}}`;
   return `<!doctype html><html amp4email data-css-strict lang="${escapeHtml(document.meta.lang)}" dir="${direction}"><head><meta charset="utf-8"><script async src="https://cdn.ampproject.org/v0.js"></script><style amp4email-boilerplate>body{visibility:hidden}</style><style amp-custom>${css}.section{padding:24px}.button{background:#2563eb;border-radius:6px;color:#fff;display:inline-block;font-weight:700;padding:12px 20px;text-decoration:none}.spacer{height:24px}</style></head><body>${body}</body></html>`;
 };