Fix null from match() on empty string in formatNumberWithCommas

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/module/numberLabel.js

@@ -13,7 +13,7 @@
  */
 const formatNumberWithCommas = (numberStr) => {
   let reversedStr = numberStr.split("").reverse().join("");
-  let groupedStr = reversedStr.match(/.{1,3}/g);
+  let groupedStr = reversedStr.match(/.{1,3}/g) || [];
   let joinedStr = groupedStr.join(",");
   let finalStr = joinedStr.split("").reverse().join("");