fix: replace nested button with div[role=button] on queue cards

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/frontend/src/routes/admin/queues/+page.svelte

@@ -131,13 +131,16 @@
   <div class="flex flex-wrap gap-3 mb-6 px-3 sm:px-0">
     {#each queues as queue (queue.name)}
       {@const isSelected = selectedQueue === queue.name}
-      <button
+      <div
+        role="button"
+        tabindex="0"
         class={`flex-1 min-w-48 rounded-lg border p-4 text-left transition-colors cursor-pointer ${
           isSelected
             ? "border-primary/50 bg-primary/5"
             : "border-border/40 bg-card hover:border-border/70"
         }`}
         onclick={() => selectQueue(queue.name)}
+        onkeydown={(e) => e.key === "Enter" && selectQueue(queue.name)}
         aria-pressed={isSelected}
       >
         <div class="flex items-center justify-between mb-3">
@@ -182,7 +185,7 @@
             <span class="text-muted-foreground">empty</span>
           {/if}
         </div>
-      </button>
+      </div>
     {/each}
   </div>