Add audit trail and filters

Implements audit trail view for item approvals, adds approval date range filtering to moderation queue, and wires up UI and backend components (Approval History page, ItemApprovalHistory component, materialized view-based history, and query/filters integration) to support compliant reporting and time-based moderation filtering.

src/App.tsx

@@ -79,6 +79,7 @@ const ErrorLookup = lazy(() => import("./pages/admin/ErrorLookup"));
 const TraceViewer = lazy(() => import("./pages/admin/TraceViewer"));
 const RateLimitMetrics = lazy(() => import("./pages/admin/RateLimitMetrics"));
 const MonitoringOverview = lazy(() => import("./pages/admin/MonitoringOverview"));
+const ApprovalHistory = lazy(() => import("./pages/admin/ApprovalHistory"));
 
 // User routes (lazy-loaded)
 const Profile = lazy(() => import("./pages/Profile"));
@@ -387,7 +388,15 @@ function AppContent(): React.JSX.Element {
                     } 
                   />
                   <Route 
-                    path="/admin/error-lookup" 
+                    path="/admin/approval-history" 
+                    element={
+                      <AdminErrorBoundary section="Approval History">
+                        <ApprovalHistory />
+                      </AdminErrorBoundary>
+                    } 
+                  />
+                  <Route 
+                    path="/admin/error-lookup"
                     element={
                       <AdminErrorBoundary section="Error Lookup">
                         <ErrorLookup />