Move formatRelativeDate() to formatText util, add util tests

app/utils/format-text.js

@@ -12,3 +12,23 @@ export function capitalize(text) {
   if (typeof text !== 'string' || !text) return '';
   return text.charAt(0).toUpperCase() + text.slice(1);
 }
+
+export function formatRelativeDate(timestamp) {
+  if (!timestamp) return '';
+  const date = new Date(timestamp * 1000);
+  const now = new Date();
+  const diffMs = now - date;
+  const diffMin = Math.floor(diffMs / 60000);
+  const diffHr = Math.floor(diffMin / 60);
+  const diffDay = Math.floor(diffHr / 24);
+
+  if (diffMin < 1) return 'just now';
+  if (diffMin < 60) return `${diffMin} min ago`;
+  if (diffHr < 24) return `${diffHr} hr ago`;
+  if (diffDay < 7) return `${diffDay} day${diffDay === 1 ? '' : 's'} ago`;
+  return date.toLocaleDateString(undefined, {
+    year: 'numeric',
+    month: 'short',
+    day: 'numeric',
+  });
+}