fix bug

Author: jihe520

frontend/src/components/Bubble.vue

@@ -3,10 +3,12 @@ import { cn } from '@/lib/utils'
 import type { HTMLAttributes } from 'vue'
 import { marked } from 'marked'
 import { computed } from 'vue'
+import { AgentType } from '@/utils/enum'
+
 
 interface BubbleProps {
   type: 'agent' | 'user'
-  agentType?: 'CoderAgent' | 'WriterAgent'
+  agentType?: AgentType
   class?: HTMLAttributes['class']
   content: string
 }

frontend/src/components/ChatArea.vue

@@ -31,7 +31,7 @@ const sendMessage = () => {
           <Bubble v-if="message.msg_type === 'user'" type="user" :content="message.content || ''" />
           <!-- agent 消息（CoderAgent/WriterAgent，只显示 content） -->
           <Bubble v-else-if="message.msg_type === 'agent'" type="agent" :agentType="message.agent_type"
-            :content="message.content" />
+            :content="message.content || ''" />
           <!-- 系统消息 -->
           <SystemMessage v-else-if="message.msg_type === 'system'" :content="message.content || ''"
             :type="message.type" />