Drop the redundant empty-items line on the list view

The summary line already shows "No items yet." when a list has no items;
remove the second one below the (empty) item list.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/views/ListView.vue

@@ -109,8 +109,6 @@ async function onCreate() {
         </template>
       </draggable>
 
-      <p v-else class="muted">No items yet &mdash; add one below.</p>
-
       <form class="form form--new-list" @submit.prevent="onCreate">
         <label>
           <span>New item</span>