Constrain email table sizing around intrinsic image widths

packages/email-renderer/test/image-accessibility.test.ts

@@ -17,6 +17,8 @@ test("meaningful image alt and explicit dimensions survive MJML round trip", asy
   const rendered = await renderEmail(documentFor(false), { mjml: true });
   if (!rendered.ok) throw new Error("Render failed");
   expect(rendered.value.parts.text.content).toContain("Accessible & descriptive");
+  expect(rendered.value.parts.html.content.match(/table-layout:fixed/g)).toHaveLength(2);
+  expect(rendered.value.parts.html.content).toContain("max-width:100%;width:600px");
   expect(rendered.value.exports!.mjml).toContain('width="320px" height="180px"');
   let id = 0;
   const imported = importMjml(rendered.value.exports!.mjml!, { id: () => `n${++id}` });