fix(math): set displaystyle and Cambria Math font on MathML output (SD-2404) (#2622)

Set displaystyle=true only on display math (m:oMathPara) per ECMA-376
spec — inline math uses cramped mode with smaller fractions and limits as
subscripts. Set display=block for m:oMathPara. Use Cambria Math as
preferred math font to match Word rendering.

Author: caio-pizzol

packages/layout-engine/painters/dom/src/features/math/omml-to-mathml.test.ts

@@ -30,6 +30,8 @@ describe('convertOmmlToMathml', () => {
     expect(result).not.toBeNull();
     expect(result!.namespaceURI).toBe(MATHML_NS);
     expect(result!.localName).toBe('math');
+    expect(result!.getAttribute('displaystyle')).toBeNull();
+    expect(result!.getAttribute('display')).toBeNull();
 
     // Should contain an <mi> for the identifier 'x'
     const mi = result!.querySelector('mi');
@@ -94,6 +96,8 @@ describe('convertOmmlToMathml', () => {
     const result = convertOmmlToMathml(omml, doc);
     expect(result).not.toBeNull();
     expect(result!.localName).toBe('math');
+    expect(result!.getAttribute('displaystyle')).toBe('true');
+    expect(result!.getAttribute('display')).toBe('block');
     // The m:oMathParaPr should be skipped (it ends with 'Pr')
     // The m:oMath child should produce content
     expect(result!.textContent).toBe('y');

packages/layout-engine/painters/dom/src/features/math/omml-to-mathml.ts

@@ -157,6 +157,12 @@ export function convertOmmlToMathml(ommlJson: unknown, doc: Document): Element |
 
   const root = ommlJson as OmmlJsonNode;
   const mathEl = doc.createElementNS(MATHML_NS, 'math');
+  mathEl.setAttribute('style', 'font-family: "Cambria Math", math');
+
+  if (root.name === 'm:oMathPara') {
+    mathEl.setAttribute('display', 'block');
+    mathEl.setAttribute('displaystyle', 'true');
+  }
 
   // For m:oMathPara, iterate over child m:oMath elements
   // For m:oMath, process directly