Address code review feedback: add guards for undefined values

- Add guard in useDataScope to return early if dataSource is undefined
- Add validation in table renderer to handle missing accessor properties
- Ensure empty string is displayed instead of undefined values

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot

packages/components/src/renderers/data-display/table.tsx

@@ -56,10 +56,11 @@ export const SimpleTableRenderer = ({ schema, className }: any) => {
             displayData.map((row: any, i: number) => (
               <TableRow key={row.id || i}>
                 {columns.map((col: any, index: number) => {
-                  const accessor = col.key || col.accessorKey;
+                  const accessor = col.key || col.accessorKey || '';
+                  const value = accessor ? row[accessor] : '';
                   return (
                     <TableCell key={col.key || col.accessorKey || index}>
-                      {row[accessor]}
+                      {value}
                     </TableCell>
                   );
                 })}

packages/react/src/context/SchemaRendererContext.tsx

@@ -37,7 +37,7 @@ export const useSchemaContext = () => {
 export const useDataScope = (path?: string) => {
   const context = useContext(SchemaRendererContext);
   const dataSource = context?.dataSource;
-  if (!path) return dataSource;
+  if (!dataSource || !path) return dataSource;
   // Simple path resolution for now. In real app might be more complex
   return path.split('.').reduce((acc, part) => acc && acc[part], dataSource);
 }