feat: 新增表格文件预览，优化知识图谱与 Agent 详情交互

- 新增 spreadsheet-preview 组件及 xlsx 解析工具，支持产物中的表格文件预览
- 优化知识图谱画布、详情面板及样式
- 调整 Agent 详情面板、聊天与消息列表交互

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend-web/src/components/workspace/chats/chat-box.tsx

@@ -33,7 +33,7 @@ import {
   ArtifactFileList,
   useArtifacts,
 } from "../artifacts";
-import { useThread } from "../messages/context";
+import { ReferenceBatchesContext, useThread } from "../messages/context";
 import { SkillDisplaySources } from "../skill-display-sources";
 
 const CLOSE_MODE = { chat: 100, artifacts: 0 };
@@ -362,10 +362,15 @@ const ChatBox: React.FC<{
   }, [sidePanelOpen]);
 
   if (disableArtifacts) {
-    return <>{children}</>;
+    return (
+      <ReferenceBatchesContext.Provider value={referenceBatches}>
+        {children}
+      </ReferenceBatchesContext.Provider>
+    );
   }
 
   return (
+    <ReferenceBatchesContext.Provider value={referenceBatches}>
     <ResizablePanelGroup
       id={`${resizableIdBase}-panels`}
       orientation="horizontal"
@@ -490,6 +495,7 @@ const ChatBox: React.FC<{
         </div>
       </ResizablePanel>
     </ResizablePanelGroup>
+    </ReferenceBatchesContext.Provider>
   );
 };