Allow undated reconstructed events

src/exhibitRegistry.tsx

@@ -37,7 +37,7 @@ function StandardWidget({ exhibit, onOpenSource }: ExhibitWidgetProps) {
 function EventWidget({ exhibit, onEditEvent }: ExhibitWidgetProps) {
   const supportCount = exhibit.supportingEvidenceIds?.length || 0
   return <div className="card-content"><h3>{exhibit.title}</h3><p>{exhibit.content}</p>
-    {exhibit.eventDate && <time>{new Date(exhibit.eventDate).toLocaleString()}</time>}
+    <time>{exhibit.eventDate ? new Date(exhibit.eventDate).toLocaleString() : 'UNDATED'}</time>
     <div className="event-actions"><span>{supportCount} SUPPORTING EXHIBIT{supportCount === 1 ? '' : 'S'}</span><button onClick={() => onEditEvent(exhibit.id)}><CalendarClock size={12}/> EDIT EVENT</button></div>
   </div>
 }