handle fs metadata.created() not present

frontend/components/DirectoryEntry.vue

@@ -59,6 +59,7 @@ async function openRenameDialog() {
                 >
                     <span>{{ entry.name }}</span>
                     <NuxtTime
+                        v-if="entry.createdAt != null"
                         :datetime="entry.createdAt * 1000"
                         class="text-muted-foreground text-sm"
                         relative