Apply brand defaults to MJML survey and product buttons

packages/email-renderer/test/mjml-brand.test.ts

@@ -8,7 +8,7 @@ const compile = createRequire(import.meta.url)("mjml");
 test("MJML preserves document metadata and global typography in compiled HTML", async () => {
   const document: BlockDocument = {
     schemaVersion: 1, kind: "email", meta: { subject: 'Brand & "News" <today>', preheader: 'Preview <safe> & useful', lang: "en" }, theme: { tokens: {} },
-    root: { id: "root", type: "layout.email-document", version: 1, props: { width: "600", fontFamily: "Georgia, serif", textColor: "#123456" }, styles: {}, slots: {
+    root: { id: "root", type: "layout.email-document", version: 1, props: { width: "600", fontFamily: "Georgia, serif", textColor: "#123456", linkColor: "#a12345" }, styles: {}, slots: {
       content: [{ id: "text", type: "content.text", version: 1, props: { text: "Brand text" }, styles: {}, slots: {} }, { id: "button", type: "content.button", version: 1, props: { label: "Brand action", href: "https://example.com" }, styles: {}, slots: {} }],
     } },
   };
@@ -35,6 +35,7 @@ test("MJML preserves document metadata and global typography in compiled HTML",
     expect(imported.value.meta.preheader).toBe(document.meta.preheader);
     expect(imported.value.root.props.fontFamily).toBe("Georgia, serif");
     expect(imported.value.root.props.textColor).toBe("#123456");
+    expect(imported.value.root.props.linkColor).toBe("#a12345");
     const rerendered = await renderEmail(imported.value, { mjml: true });
     expect(rerendered.ok).toBe(true);
   }