新增通用聊天图片预览组件

- ImagePreview / ChatImage：全屏预览、ESC 关闭、下载
- 接入工作台、访客 Widget、对话记录

web/src/pages/agent/Dashboard.tsx

@@ -6,6 +6,7 @@ import {
   ExportOutlined, BookOutlined, PictureOutlined,
 } from '@ant-design/icons'
 import EmojiPicker, { insertAtCursor } from '@/components/common/EmojiPicker'
+import { ChatImage } from '@/components/common/ImagePreview'
 import { useAuth } from '@/stores/auth'
 import {
   addSessionNote, claimSession, endSession, getAvailableAgents, getCustomers, getKnowledgeEntries,
@@ -725,7 +726,7 @@ const Dashboard = () => {
                             }`}
                           >
                             {message.type === 'image' ? (
-                              <img src={message.content} alt="聊天图片" className="max-w-64 max-h-64 rounded-lg" />
+                              <ChatImage src={message.content} alt="聊天图片" className="max-w-64 max-h-64" />
                             ) : (
                               <p className="text-sm leading-normal whitespace-pre-wrap break-words m-0">{message.content}</p>
                             )}