feat(agent): approval queue inline card + exclusion panel

新增 ApprovalQueue 视图、ApprovalInlineCard/AgentExclusionPanel 组件与 useApprovalQueue; 对话/API 适配; public 静态资源。

frontend-agent/src/components/chat/MessageItem.vue

@@ -25,7 +25,7 @@
     <!-- 发送者名称 -->
     <div v-if="message.sender_type !== 'agent'" class="message-sender-name">
       {{ senderLabel }}
-      <span v-if="message.sender_type === 'ai'" class="ai-tag">AI</span>
+      <img v-if="message.sender_type === 'ai'" src="/duckula.webp" class="duckula-avatar" alt="Duckula" />
     </div>
 
     <!-- 消息气泡 -->
@@ -196,9 +196,9 @@ const copySuccess = ref(false)
 /** 发送者标签 */
 const senderLabel = computed(() => {
   const labelMap: Record<string, string> = {
-    employee: props.message.sender_name || '员工',
+    employee: props.message.sender_name || conversationStore.currentConversation?.employee_name || '未知',
     agent: props.message.sender_name || '我',
-    ai: 'AI助手',
+    ai: 'Duckula（达寇拉）',
   }
   return labelMap[props.message.sender_type] || '未知'
 })