feat: AI writing history, Word export, roundtable dispatch chain

frontend-web/src/open-canvas/components/ai-writing/AIWritingDraftPanel.tsx

@@ -1,6 +1,7 @@
 import { FileText, PenLine } from 'lucide-react';
 
 import { useAIWritingOptional } from '../../contexts/AIWritingContext';
+import { useAIWritingHistoryOptional } from '../../contexts/AIWritingHistoryContext';
 import { useCanvasGraphContext } from '../../contexts/CanvasGraphContext';
 import { useCanvasUIContext } from '../../contexts/CanvasUIContext';
 import { assembleStreamingDraftMarkdown } from '../../hooks/useAIWritingStream';
@@ -32,8 +33,12 @@ function DraftWaitingPlaceholder() {
 
 export function AIWritingDraftPanel() {
   const writing = useAIWritingOptional();
+  const history = useAIWritingHistoryOptional();
+  const isHistoryMode = history?.isHistoryMode ?? false;
   const { artifact } = useCanvasGraphContext();
   const { isDraftEditable } = useCanvasUIContext();
+  // 历史回看与写作完成态一致：Tiptap + 目录；流式生成中仍走 Markdown 预览
+  const showCompletedDraftView = isDraftEditable || isHistoryMode;
 
   const writingStatus = writing?.state.status;
   // 仅当章节仍在累积时走流式 Markdown；draft_ready 清空 sections 后即使 status 尚未切走也进画布
@@ -96,7 +101,8 @@ export function AIWritingDraftPanel() {
         <div className="flex-1 overflow-hidden">
           <TextArtifactRenderer
             content={textContent}
-            isStreaming={!isDraftEditable}
+            isStreaming={!showCompletedDraftView}
+            readOnly={isHistoryMode}
           />
         </div>
       </div>