docs(ui): add changeset and docs for TableRoot loading prop

Signed-off-by: Jonathan Roebuck <jroebuck@spotify.com>

.changeset/bui-table-root-loading-prop.md

@@ -0,0 +1,7 @@
+---
+'@backstage/ui': patch
+---
+
+Added a `loading` prop and `data-loading` data attribute to `TableRoot`, allowing consumers to distinguish between stale data and initial loading states. Both `stale` and `loading` set `aria-busy` on the table.
+
+Affected components: Table

docs-ui/src/app/components/table/props-definition.tsx

@@ -430,6 +430,17 @@ export const tableRootPropDefs: Record<string, PropDef> = {
       </>
     ),
   },
+  loading: {
+    type: 'boolean',
+    default: 'false',
+    description: (
+      <>
+        Whether the table is in a loading state (e.g., initial data fetch). Adds{' '}
+        <Chip>aria-busy</Chip> attribute and <Chip>data-loading</Chip> data
+        attribute for styling.
+      </>
+    ),
+  },
 };
 
 export const columnPropDefs: Record<string, PropDef> = {