Adopt shared WebUI structural primitives

webui/src/features/reporting/ProviderReportWorkspace.tsx

@@ -7,6 +7,7 @@ import { ContentGrid, ActionToolbar,
   DismissibleAlert,
   IconButton,
   MetricCard,
+  StatePanel,
   StatusBadge,
   hasScope,
   type ApiSettings,
@@ -175,7 +176,7 @@ export function ProviderReportWorkspace({ settings, auth, report }: {
       </div>
       {execution ?
         <>
-          <ActionToolbar className="reporting-output-toolbar">
+          <ActionToolbar surface="panel-header" className="reporting-output-toolbar">
             <span>Generated {formatDateTime(execution.generated_at)}</span>
             {report.export_formats.includes("csv") &&
               <IconButton label="Download CSV" icon={<Download size={17} />} variant="ghost" onClick={() => void download("csv")} />
@@ -188,7 +189,7 @@ export function ProviderReportWorkspace({ settings, auth, report }: {
             <ProviderResult execution={execution} />
           </div>
         </> :
-        <div className="reporting-empty">Select the parameters and run this governed report.</div>
+        <StatePanel size="fill" description="Select the parameters and run this governed report." />
       }
     </>
   );