fix(page-number): fall back for unknown formats

Author: luccas-harbour

packages/layout-engine/contracts/src/index.ts

@@ -474,6 +474,8 @@ export function formatPageNumber(pageNumber: number, format: PageNumberFormat):
       return toRepeatedLetter(num, 97);
     case 'numberInDash':
       return `- ${num} -`;
+    default:
+      return String(num);
   }
 }
 

packages/layout-engine/layout-engine/src/pageNumbering.test.ts

@@ -27,6 +27,10 @@ describe('formatPageNumber', () => {
       expect(formatPageNumber(-1, 'decimal')).toBe('1');
       expect(formatPageNumber(-100, 'decimal')).toBe('1');
     });
+
+    it('should fall back to decimal for unsupported runtime formats', () => {
+      expect(formatPageNumber(5, 'chicago' as never)).toBe('5');
+    });
   });
 
   describe('numberInDash format', () => {