fix(webui): resolve document status grouping issue in DocumentManager

- Fix documents being grouped by status after pagination and sorting
- Use backend-sorted data directly from currentPageDocs instead of re-grouping
- Preserve backend sort order to prevent status-based grouping
- Maintain backward compatibility with legacy docs structure
- Ensure all sorting fields (file name, dates, ID) work correctly without status grouping

The issue occurred because the frontend was re-grouping already-sorted data
from the backend by status, breaking the intended sort order. Now documents
are displayed in the exact order returned by the backend API.

Fixes: Document list sorting by file name was grouping by status instead of
maintaining proper sort order across all documents.

lightrag_webui/src/features/DocumentManager.tsx

@@ -183,7 +183,7 @@ export default function DocumentManager() {
   const setDocumentsPageSize = useSettingsStore.use.setDocumentsPageSize()
 
   // New pagination state
-  const [, setCurrentPageDocs] = useState<DocStatusResponse[]>([])
+  const [currentPageDocs, setCurrentPageDocs] = useState<DocStatusResponse[]>([])
   const [pagination, setPagination] = useState<PaginationInfo>({
     page: 1,
     page_size: documentsPageSize,
@@ -292,6 +292,16 @@ export default function DocumentManager() {
   type DocStatusWithStatus = DocStatusResponse & { status: DocStatus };
 
   const filteredAndSortedDocs = useMemo(() => {
+    // Use currentPageDocs directly if available (from paginated API)
+    // This preserves the backend's sort order and prevents status grouping
+    if (currentPageDocs && currentPageDocs.length > 0) {
+      return currentPageDocs.map(doc => ({
+        ...doc,
+        status: doc.status as DocStatus
+      })) as DocStatusWithStatus[];
+    }
+
+    // Fallback to legacy docs structure for backward compatibility
     if (!docs) return null;
 
     // Create a flat array of documents with status information
@@ -324,7 +334,7 @@ export default function DocumentManager() {
     }
 
     return allDocuments;
-  }, [docs, sortField, sortDirection, statusFilter, sortDocuments]);
+  }, [currentPageDocs, docs, sortField, sortDirection, statusFilter, sortDocuments]);
 
   // Calculate current page selection state (after filteredAndSortedDocs is defined)
   const currentPageDocIds = useMemo(() => {