fix: make playlist entries easier identifiable

src/components/playlist/APlaylistEntryEditor.vue

 <template>
   <component
     :is="as"
-    class="tw-bg-gray-50 dark:tw-bg-neutral-800 tw-p-3 tw-rounded tw-flex tw-gap-2 tw-items-center"
+    class="tw-bg-gray-50 tw-border dark:tw-bg-neutral-800 dark:tw-border-neutral-700 tw-p-3 tw-rounded tw-flex tw-gap-2 tw-items-center"
   >
     <div>
       <icon-system-uicons-drag-vertical