Add item-level approval history

Introduce ItemLevelApprovalHistory component to display which specific submission items were approved, when, and by whom, and integrate it into QueueItem between metadata and audit trail. The component shows item names, approval timestamps, action types, and reviewer info.

src/components/moderation/QueueItem.tsx

@@ -23,6 +23,7 @@ import { QueueItemActions } from './renderers/QueueItemActions';
 import { SubmissionMetadataPanel } from './SubmissionMetadataPanel';
 import { AuditTrailViewer } from './AuditTrailViewer';
 import { RawDataViewer } from './RawDataViewer';
+import { ItemLevelApprovalHistory } from './ItemLevelApprovalHistory';
 
 interface QueueItemProps {
   item: ModerationItem;
@@ -330,6 +331,15 @@ export const QueueItem = memo(({
         {item.type === 'content_submission' && (
           <div className="mt-6 space-y-4">
             <SubmissionMetadataPanel item={item} />
+            
+            {/* Item-level approval history */}
+            {item.submission_items && item.submission_items.length > 0 && (
+              <ItemLevelApprovalHistory 
+                items={item.submission_items}
+                reviewerProfile={item.reviewer_profile}
+              />
+            )}
+            
             <AuditTrailViewer submissionId={item.id} />
           </div>
         )}