feat(help-center): enable drag-and-drop category reordering (#13706)

app/javascript/dashboard/components-next/HelpCenter/Pages/ArticlePage/ArticleList.vue

@@ -58,18 +58,22 @@ const openArticle = id => {
   }
 };
 
-const onReorder = reorderedGroup => {
-  store.dispatch('articles/reorder', {
-    reorderedGroup,
-    portalSlug: route.params.portalSlug,
-  });
+const onReorder = async reorderedGroup => {
+  try {
+    await store.dispatch('articles/reorder', {
+      reorderedGroup,
+      portalSlug: route.params.portalSlug,
+    });
+  } catch {
+    useAlert(t('HELP_CENTER.REORDER_ARTICLE.API.ERROR_MESSAGE'));
+  }
 };
 
 const onDragEnd = () => {
-  // Reuse existing positions to maintain order within the current group
+  // Collect and sort existing positions, falling back to index+1 for null/0 values
   const sortedArticlePositions = localArticles.value
-    .map(article => article.position)
-    .sort((a, b) => a - b); // Use custom sort to handle numeric values correctly
+    .map((article, index) => article.position || index + 1)
+    .sort((a, b) => a - b);
 
   const orderedArticles = localArticles.value.map(article => article.id);