feat(web): load export, preview, and charts only when opened

The login shell was downloading the document engines with the workbench. Those modules now load on click or when a matching block appears, and a failed chunk can be retried without submitting an edit. Co-authored-by: Cursor <cursoragent@cursor.com>
2026-09-19 09:51:04 +00:00
parent 1b17e01ce7
commit 17f7fed1db
11 changed files with 242 additions and 100 deletions
@@ -18,7 +18,7 @@
 | Cursor | audit-b2-authz-hardening | fix/audit-b2-authz-hardening | - | authz | done |
 | Cursor | audit-b3-sse-events | fix/audit-b3-sse-events | - | chat+events | done |
 | Cursor | audit-b4-frontend | fix/audit-b4-frontend | - | web | done |
-| Cursor | audit-remainder-backlog | docs/audit-remediation-backlog | - | audit | done |
+| Cursor-Auto | 2026-09-19-audit-remainder-closeout | fix/audit-remainder-closeout | - | audit-remainder | in_progress |
 | Cursor-Auto | 2026-09-19-remove-control-center | fix/remove-control-center | - | controlcenter | done |
 | Cursor-Auto | 2026-09-17-control-center-server | feature/control-center-server | - | controlcenter | cancelled |
 | Kimi | 2026-09-18-user-manual | feature/user-manual | .worktrees/feature-user-manual | docs | done |
@@ -46,10 +46,10 @@ updated: 2026-09-19
 | FE 缓存 | done（版本字段）。窗口缓存写入 `{schema,data}`，无 schema 的旧载荷丢弃。`window cache: 无 schema` |
 | FE lucide | 关闭理由：`package-lock.json` 锁定 `lucide-react@1.42.0`，来源 `registry.npmjs.org`，带 integrity。`^1.16.0` 是合法的 1.x 范围，不是来源不明的包 |
 | M7 | done（出站意图 + 同键重放）。`document_content_projections` 与账本同一事务写入；投影成功才销账。`TestDocRevision_PatchOrder_RetryProjectsWithoutSecondLedgerCommit`。账本库与正文库仍不是一个 SQL 事务，进程退出后靠未投影行重放，不靠客户端记忆 |
-| FE App.tsx | 仍开放。4600 行拆 hook 是独立重构，本轮未拆，避免在没有行为变更需求时改写工作台 |
+| FE App.tsx | 部分。登录壳不再静态引用导出引擎、文件预览、管理台、块编辑器和图表。入口包 2.83 MB → 1.00 MB（br 626 KB → 235 KB）。`loginShellImports.test.ts`。工作台主体仍在 `App.tsx`，未按 hook 拆文件 |
 | H1-del | 关闭理由：`allowLegacyTestPrincipal` 仍被 `AllowInMemory && ContextDbHost==""` 的 dev/test 内存测试使用。删除会把这批测试变成未登录 401。保留告警，删除另开、先改测试夹具 |

-仍开放：FE `App.tsx` 拆分、rdev S2/S3 与 P2–P4、首次加载 U1/U3–U7、dev 容器重建与治理库 PG。本分支已跑通 `cd web && npm test`（tsx 407 + vitest 32，全过）和 `npm run build`（主包 `index-*.js` 仍约 2.83 MB，U3 拆包未做）。H2 批注/审计的项目成员检查在 Postgres 上走 `RequireProjectAccess`；内存授权器在无库时把任意正用户 id 视为成员，这是 `TestAuthorizeDocRevision_ReviewerAndNonMemberCannotWrite` 的隔离前提，不能改成默认拒绝。H2 的 HTTP 负例因此要在 `TEST_DATABASE_URL` 上补，本机未设置该变量。M7 的投影意图已随账本提交（goose `00053`）；容器 schema 仍是 52，要等占槽重建后才升到 53。
+仍开放：rdev S2/S3 与 P2–P4、首次加载 U1/U4–U7、dev 容器重建与治理库 PG。U3 只完成登录壳拆包（入口包 1.00 MB / br 235 KB），消息公式引擎仍在入口图里。本分支已跑通 `cd web && npm test` 与 `npm run build`。H2 批注/审计的项目成员检查在 Postgres 上走 `RequireProjectAccess`；内存授权器在无库时把任意正用户 id 视为成员，这是 `TestAuthorizeDocRevision_ReviewerAndNonMemberCannotWrite` 的隔离前提，不能改成默认拒绝。H2 的 HTTP 负例因此要在 `TEST_DATABASE_URL` 上补，本机未设置该变量。M7 的投影意图已随账本提交（goose `00053`）；容器 schema 仍是 52，要等占槽重建后才升到 53。

 红线关闭（不是实现）：

@@ -96,7 +96,7 @@

 ## 2026-09-17 首次加载性能专项

-首次加载与重启首访性能优化：**partial**（U2 静态交付已验收；不改变现有功能 done/发布门禁结论）。[审计](../audit/2026-09-17-initial-load-performance-audit.md) · [方案](../remediation/2026-09-17-initial-load-performance-plan.md) · [U2 报告](../test-reports/2026-09-17-initial-load-perf-u2-test-report.md)。U2：自托管字体 + br/gzip + assets 404；主 JS 传输 2.82 MB → ~624 KB。U1/U3–U7 未完成。mutex `web + static-delivery`（U2 done）/ `loading-performance-audit`。
+首次加载与重启首访性能优化：**partial**（U2 静态交付已验收；U3 只做了登录壳拆包，未关闭）。[审计](../audit/2026-09-17-initial-load-performance-audit.md) · [方案](../remediation/2026-09-17-initial-load-performance-plan.md) · [U2 报告](../test-reports/2026-09-17-initial-load-perf-u2-test-report.md)。U2：自托管字体 + br/gzip。U3 进展（`fix/audit-remainder-closeout`）：导出、预览、管理台、块编辑器、Mermaid/公式改为点击或出现时再加载。入口包 `index-*.js` 由 2.83 MB / br 626 KB 降到 1.00 MB / br 235 KB。消息气泡里的公式引擎仍在入口图里。U1、U4–U7 未做。mutex `web + static-delivery`（U2 done）/ `loading-performance-audit`。

 ## 2026-09-17 文档编制人兼任方案

@@ -5,7 +5,6 @@ import { InputArea } from './components/chat/InputArea';
 import { SlimTabBar } from './components/doc/SlimTabBar';
 import { DeckDrawer } from './components/doc/DeckDrawer';
 import { BlockRenderer } from './components/doc/BlockRenderer';
-import { BlockEditorModal } from './components/doc/BlockEditorModal';
 import { DocumentRevisionToolbar } from './components/doc/DocumentRevisionToolbar';
 import { CommentSidePanel } from './components/doc/CommentSidePanel';
 import { DocGovActionBar } from './components/doc/DocGovActionBar';
@@ -106,17 +105,16 @@ import { StaleDocumentNotice } from './components/workflow/StaleDocumentNotice';
 import { StageAdvanceBanner } from './components/workflow/StageAdvanceBanner';
 import { deriveReplyTitle } from './features/replyExport/title';
 import { copyRichReplyToClipboard, copyMarkdownReply } from './features/replyExport/clipboard';
-import { downloadMarkdownReply, downloadDocxReply } from './features/replyExport/download';
+import { downloadMarkdownReply } from './features/replyExport/download';
 import { ProposalConfirmCard } from './components/doc/ProposalConfirmCard';
 import { UserProjectRightsModal } from './components/user/UserProjectRightsModal';
 import { UserSettingsModal } from './components/user/UserSettingsModal';
-import { AdminConsoleView } from './components/admin/console/AdminConsoleView';
+import { OnDemand } from './components/lazy/OnDemand';
 import { DocVisibilityModal } from './components/doc/DocVisibilityModal';
 import { CreateProjectModal, type CreateProjectConfirmData } from './components/project/CreateProjectModal';
 import { ProjectMembersModal } from './components/project/ProjectMembersModal';
 import { ProjectSettingsModal } from './components/project/ProjectSettingsModal';
 import { fetchProjectSettings } from './api/projectSettings';
-import { FilePreviewPanel } from './components/doc/preview/FilePreviewPanel';
 import { ShieldAlert } from 'lucide-react';
 import { LoginView } from './components/auth/LoginView';
 import { FirstLoginPasswordModal } from './components/auth/FirstLoginPasswordModal';
@@ -153,8 +151,6 @@ import {
  hasPermission,
  filterVisibleDeliverablesWithRBAC,
 } from './engine/rbac';
-import { exportDocumentToDocx } from './engine/docxRenderer';
-import { exportDocumentToXlsx } from './engine/xlsxRenderer';
 import {
  findMatchingBlockForReview,
  createRejectConfirmationCard,
@@ -225,7 +221,6 @@ import { HistoryCalendar } from './components/history/HistoryCalendar';
 import { ChatSearchModal } from './components/history/ChatSearchModal';
 import { DigestTimelineModal } from './components/history/DigestTimelineModal';
 import { navigateToAnchor, parseAnchorHash, resolveTurnAnchorId } from './engine/anchorNavigator';
-import { ChatExportModal } from './components/history/ChatExportModal';
 import { useUnreadMarks } from './hooks/useUnreadMarks';
 import { CategoryDock } from './components/chat/CategoryDock';
 import { fetchChatCategories, fetchChatDates, mapTaskStatusToMessageStatus } from './api/chatWindow';
@@ -284,6 +279,15 @@ export {
  MOCK_USERS,
 } from '@demo-seeds';

+const loadFilePreviewPanel = () =>
+  import('./components/doc/preview/FilePreviewPanel').then((m) => ({ default: m.FilePreviewPanel }));
+const loadAdminConsoleView = () =>
+  import('./components/admin/console/AdminConsoleView').then((m) => ({ default: m.AdminConsoleView }));
+const loadChatExportModal = () =>
+  import('./components/history/ChatExportModal').then((m) => ({ default: m.ChatExportModal }));
+const loadBlockEditorModal = () =>
+  import('./components/doc/BlockEditorModal').then((m) => ({ default: m.BlockEditorModal }));
+
 export default function App() {
  // Wave 2：启动时幂等剔除 localStorage 中的 demo seed 残留（须先于 load*）
  purgeDemoSeedsFromLocalStorage();
@@ -3653,15 +3657,16 @@ export default function App() {
  // 导出 DOCX (Word 渲染器)
  const handleExportDocx = async () => {
    try {
+      const { exportDocumentToDocx } = await import('./engine/docxRenderer');
      await exportDocumentToDocx(docAST);
    } catch (err) {
      console.error('导出 DOCX 失败:', err);
    }
  };

-  // 导出单条智能体回复 DOCX (轻量专属 Word 导出)
  const handleExportReplyDocx = async (message: ChatMessage) => {
    try {
+      const { downloadDocxReply } = await import('./features/replyExport/downloadDocx');
      await downloadDocxReply(message.content || '', undefined, {
        createdAt: message.createdAt || message.timestamp,
      });
@@ -3670,10 +3675,9 @@ export default function App() {
    }
  };

-
-  // 导出 XLSX (Excel 渲染器)
  const handleExportXlsx = async () => {
    try {
+      const { exportDocumentToXlsx } = await import('./engine/xlsxRenderer');
      await exportDocumentToXlsx(docAST);
    } catch (err) {
      console.error('导出 XLSX 失败:', err);
@@ -3996,15 +4000,19 @@ export default function App() {
  // 全屏系统管理台：与工作台并列的顶层视图，不经过 AppShell
  if (view === 'admin') {
    return (
-      <AdminConsoleView
-        currentUser={currentUser}
-        env={systemEnv}
-        onExit={() => setView('workbench')}
-        onUsersChanged={async () => {
-          const users = await authClient.getAdminUsers();
-          setAllUsers(users);
+      <OnDemand
+        label="管理台"
+        load={loadAdminConsoleView}
+        componentProps={{
+          currentUser,
+          env: systemEnv,
+          onExit: () => setView('workbench'),
+          onUsersChanged: async () => {
+            const users = await authClient.getAdminUsers();
+            setAllUsers(users);
+          },
+          onRolesChanged: (newRoles: RoleDefinition[]) => setRoles(newRoles),
        }}
-        onRolesChanged={(newRoles) => setRoles(newRoles)}
      />
    );
  }
@@ -4117,11 +4125,15 @@ export default function App() {
              />
            )}
            {isExportOpen && (
-              <ChatExportModal
-                isOpen={isExportOpen}
-                onClose={() => setIsExportOpen(false)}
-                sessionId={activeSessionId}
-                dayStack={chatWindow.displayDayStack}
+              <OnDemand
+                label="聊天导出"
+                load={loadChatExportModal}
+                componentProps={{
+                  isOpen: isExportOpen,
+                  onClose: () => setIsExportOpen(false),
+                  sessionId: activeSessionId,
+                  dayStack: chatWindow.displayDayStack,
+                }}
              />
            )}
            <div style={{ position: 'relative', flex: 1, minHeight: 0, display: 'flex', flexDirection: 'column' }}>
@@ -4356,11 +4368,15 @@ export default function App() {
              );
              if (isUploadedFile && activeDeliverable) {
                return (
-                  <FilePreviewPanel
-                    deliverable={activeDeliverable}
-                    onOpenDocVisibility={() => {
-                      setTargetDocForVisibility(activeDeliverable);
-                      setDocVisibilityModalOpen(true);
+                  <OnDemand
+                    label="文件预览"
+                    load={loadFilePreviewPanel}
+                    componentProps={{
+                      deliverable: activeDeliverable,
+                      onOpenDocVisibility: () => {
+                        setTargetDocForVisibility(activeDeliverable);
+                        setDocVisibilityModalOpen(true);
+                      },
                    }}
                  />
                );
@@ -4466,11 +4482,15 @@ export default function App() {

            {/* 块就地编辑弹窗 (支持富文本工具栏、多维表格与未保存拦截) */}
            {editorSession && (
-              <BlockEditorModal
-                block={editorSession.block}
-                actorLabel={`${currentUser.name} (${currentUser.position || '成员'})`}
-                onSave={handleSaveBlockEdit}
-                onClose={closeBlockEditor}
+              <OnDemand
+                label="块编辑器"
+                load={loadBlockEditorModal}
+                componentProps={{
+                  block: editorSession.block,
+                  actorLabel: `${currentUser.name} (${currentUser.position || '成员'})`,
+                  onSave: handleSaveBlockEdit,
+                  onClose: closeBlockEditor,
+                }}
              />
            )}

@@ -2,7 +2,7 @@ import React, { useState, useRef, useEffect } from 'react';
 import { Copy, Check, Bookmark, Download, ChevronDown, FileText, FileCode } from 'lucide-react';
 import { ChatMessage } from '../../types/workbench';
 import { copyRichReplyToClipboard, copyMarkdownReply } from '../../features/replyExport/clipboard';
-import { downloadMarkdownReply, downloadDocxReply } from '../../features/replyExport/download';
+import { downloadMarkdownReply } from '../../features/replyExport/download';

 export interface ReplyActionBarProps {
  message: ChatMessage;
@@ -334,6 +334,7 @@ export const ReplyActionBar: React.FC<ReplyActionBarProps> = ({
                  if (onExportDocx) {
                    await onExportDocx(message);
                  } else {
+                    const { downloadDocxReply } = await import('../../features/replyExport/downloadDocx');
                    await downloadDocxReply(message.content || '', undefined, {
                      createdAt: message.createdAt || message.timestamp,
                    });
@@ -7,14 +7,18 @@ import { HeadingBlockView } from './blocks/HeadingBlockView';
 import { ParagraphBlockView } from './blocks/ParagraphBlockView';
 import { TableBlockView } from './blocks/TableBlockView';
 import { CalloutBlockView } from './blocks/CalloutBlockView';
-import { MermaidBlockView } from './blocks/MermaidBlockView';
-import { MathBlockView } from './blocks/MathBlockView';
 import { ListBlockView } from './blocks/ListBlockView';
+import { OnDemand } from '../lazy/OnDemand';
 import { BlockContextMenu } from './BlockContextMenu';
 import { canAddBlockComment } from '../../lib/commentPolicy';
 import { documentBlockDomAttrs } from '../../lib/documentBlockDom';
 import { Plus, ArrowUp, ArrowDown, Trash2, MessageSquare } from 'lucide-react';

+const loadMermaidBlock = () =>
+  import('./blocks/MermaidBlockView').then((m) => ({ default: m.MermaidBlockView }));
+const loadMathBlock = () =>
+  import('./blocks/MathBlockView').then((m) => ({ default: m.MathBlockView }));
+
 export interface BlockRendererProps {
  ast: DocumentAST;
  currentRole: UserRole;
@@ -75,9 +79,21 @@ export const BlockRenderer: React.FC<BlockRendererProps> = ({
      case 'callout':
        return <CalloutBlockView block={block} />;
      case 'mermaid':
-        return <MermaidBlockView block={block} />;
+        return (
+          <OnDemand
+            label="图表"
+            load={loadMermaidBlock}
+            componentProps={{ block }}
+          />
+        );
      case 'math':
-        return <MathBlockView block={block} />;
+        return (
+          <OnDemand
+            label="公式"
+            load={loadMathBlock}
+            componentProps={{ block }}
+          />
+        );
      case 'list':
        return <ListBlockView block={block} />;
      case 'divider':
@@ -15,12 +15,14 @@ import {
  ShieldCheck,
 } from 'lucide-react';
 import { DeliverableItem } from '../../../types/workbench';
-import { DocxViewer } from './renderers/DocxViewer';
-import { PdfViewer } from './renderers/PdfViewer';
-import { ExcelViewer } from './renderers/ExcelViewer';
 import { ImageViewer } from './renderers/ImageViewer';
+import { PdfViewer } from './renderers/PdfViewer';
 import { PptViewer } from './renderers/PptViewer';
 import { TextViewer } from './renderers/TextViewer';
+import { OnDemand } from '../../lazy/OnDemand';
+
+const loadDocxViewer = () => import('./renderers/DocxViewer').then((m) => ({ default: m.DocxViewer }));
+const loadExcelViewer = () => import('./renderers/ExcelViewer').then((m) => ({ default: m.ExcelViewer }));

 interface FilePreviewPanelProps {
  deliverable: DeliverableItem;
@@ -273,11 +275,23 @@ export const FilePreviewPanel: React.FC<FilePreviewPanelProps> = ({
    }
    switch (fileType) {
      case 'docx':
-        return <DocxViewer fileRaw={fileRaw} fileUrl={fileUrl} fileName={fileName} />;
+        return (
+          <OnDemand
+            label="Word 预览"
+            load={loadDocxViewer}
+            componentProps={{ fileRaw, fileUrl, fileName }}
+          />
+        );
      case 'pdf':
        return <PdfViewer fileRaw={fileRaw} fileUrl={fileUrl} fileName={fileName} />;
      case 'excel':
-        return <ExcelViewer fileRaw={fileRaw} fileUrl={fileUrl} fileName={fileName} />;
+        return (
+          <OnDemand
+            label="表格预览"
+            load={loadExcelViewer}
+            componentProps={{ fileRaw, fileUrl, fileName }}
+          />
+        );
      case 'image':
        return <ImageViewer fileRaw={fileRaw} fileUrl={fileUrl} fileName={fileName} />;
      case 'ppt':
@@ -0,0 +1,52 @@
+import { Component, lazy, Suspense, useMemo, useState, type ComponentType, type ReactNode } from 'react';
+
+type BoundaryProps = {
+  label: string;
+  onRetry: () => void;
+  children: ReactNode;
+};
+
+type BoundaryState = { error: Error | null };
+
+/** Catches a failed dynamic import. Retry builds a new lazy() so a rejected chunk is not sticky. */
+export class LazyBoundary extends Component<BoundaryProps, BoundaryState> {
+  state: BoundaryState = { error: null };
+
+  static getDerivedStateFromError(error: Error): BoundaryState {
+    return { error };
+  }
+
+  render() {
+    if (this.state.error) {
+      return (
+        <div role="alert" style={{ padding: 12, fontSize: 13 }}>
+          <p style={{ margin: '0 0 8px' }}>
+            {this.props.label}加载失败，可重试。这次失败不会提交文档或聊天动作。
+          </p>
+          <button type="button" onClick={this.props.onRetry}>
+            重试
+          </button>
+        </div>
+      );
+    }
+    return (
+      <Suspense fallback={<div style={{ padding: 12, fontSize: 13 }}>{this.props.label}加载中…</div>}>
+        {this.props.children}
+      </Suspense>
+    );
+  }
+}
+
+export function OnDemand<P extends object>(props: {
+  label: string;
+  load: () => Promise<{ default: ComponentType<P> }>;
+  componentProps: P;
+}) {
+  const [attempt, setAttempt] = useState(0);
+  const Comp = useMemo(() => lazy(props.load), [attempt, props.load]);
+  return (
+    <LazyBoundary key={attempt} label={props.label} onRetry={() => setAttempt((n) => n + 1)}>
+      <Comp {...props.componentProps} />
+    </LazyBoundary>
+  );
+}
@@ -1,7 +1,4 @@
-import { Packer } from 'docx';
 import { deriveReplyTitle, sanitizeFilename } from './title';
-import { markdownToBlockAST } from '../../engine/markdownToBlock';
-import { buildDocxModel } from '../../engine/docxRenderer';

 export interface DownloadOptions {
  includeSource?: boolean;
@@ -42,53 +39,3 @@ export function downloadMarkdownReply(
  return { filename };
 }

-/**
- * 触发 Word (.docx) 专用轻量排版导出并直接下载
- */
-export async function downloadDocxReply(
-  markdown: string,
-  title?: string,
-  options: DownloadOptions = {}
-): Promise<{ filename: string; blob: Blob }> {
-  const effectiveTitle = title || deriveReplyTitle(markdown, options.createdAt);
-  const dateStr = new Date().toISOString().substring(0, 10);
-  const baseName = sanitizeFilename(effectiveTitle);
-  const filename = options.filenameOverride || `${baseName}_${dateStr}.docx`;
-
-  let exportContent = (markdown || '').trim();
-  if (options.includeSource) {
-    const metaTime = options.createdAt || new Date().toLocaleString();
-    exportContent += `\n\n---\n*来源：水木东方项目助手回复 · 生成时间：${metaTime}*`;
-  }
-
-  const ast = markdownToBlockAST(exportContent, {
-    docId: `reply-docx-${Date.now()}`,
-    title: effectiveTitle,
-    taskKey: 'reply_export',
-    version: 'V1.0',
-    category: 'private',
-    lifecycleState: 'drafting',
-    isClaimed: true,
-    author: '智能体助手回复',
-    reviewer: '',
-    approver: '',
-    updatedAt: new Date().toISOString().replace('T', ' ').substring(0, 16),
-  });
-
-  const doc = await buildDocxModel(ast);
-  const blob = await Packer.toBlob(doc);
-
-  if (typeof window !== 'undefined' && typeof document !== 'undefined') {
-    const url = URL.createObjectURL(blob);
-    const a = document.createElement('a');
-    a.href = url;
-    a.download = filename;
-    document.body.appendChild(a);
-    a.click();
-    document.body.removeChild(a);
-    setTimeout(() => URL.revokeObjectURL(url), 1000);
-  }
-
-  return { filename, blob };
-}
-
@@ -0,0 +1,53 @@
+import { Packer } from 'docx';
+import { deriveReplyTitle, sanitizeFilename } from './title';
+import { markdownToBlockAST } from '../../engine/markdownToBlock';
+import { buildDocxModel } from '../../engine/docxRenderer';
+import type { DownloadOptions } from './download';
+
+/** Word 导出。只在点击时动态引入，避免 docx 进入登录壳。 */
+export async function downloadDocxReply(
+  markdown: string,
+  title?: string,
+  options: DownloadOptions = {}
+): Promise<{ filename: string; blob: Blob }> {
+  const effectiveTitle = title || deriveReplyTitle(markdown, options.createdAt);
+  const dateStr = new Date().toISOString().substring(0, 10);
+  const baseName = sanitizeFilename(effectiveTitle);
+  const filename = options.filenameOverride || `${baseName}_${dateStr}.docx`;
+
+  let exportContent = (markdown || '').trim();
+  if (options.includeSource) {
+    const metaTime = options.createdAt || new Date().toLocaleString();
+    exportContent += `\n\n---\n*来源：水木东方项目助手回复 · 生成时间：${metaTime}*`;
+  }
+
+  const ast = markdownToBlockAST(exportContent, {
+    docId: `reply-docx-${Date.now()}`,
+    title: effectiveTitle,
+    taskKey: 'reply_export',
+    version: 'V1.0',
+    category: 'private',
+    lifecycleState: 'drafting',
+    isClaimed: true,
+    author: '智能体助手回复',
+    reviewer: '',
+    approver: '',
+    updatedAt: new Date().toISOString().replace('T', ' ').substring(0, 16),
+  });
+
+  const doc = await buildDocxModel(ast);
+  const blob = await Packer.toBlob(doc);
+
+  if (typeof window !== 'undefined' && typeof document !== 'undefined') {
+    const url = URL.createObjectURL(blob);
+    const a = document.createElement('a');
+    a.href = url;
+    a.download = filename;
+    document.body.appendChild(a);
+    a.click();
+    document.body.removeChild(a);
+    setTimeout(() => URL.revokeObjectURL(url), 1000);
+  }
+
+  return { filename, blob };
+}
@@ -0,0 +1,39 @@
+import assert from 'node:assert/strict';
+import { readFileSync } from 'node:fs';
+import { test } from 'node:test';
+
+function staticImports(rel: string): string[] {
+  const text = readFileSync(new URL(rel, import.meta.url), 'utf8');
+  return text
+    .split('\n')
+    .filter((line) => /^\s*import\s/.test(line) && !line.includes('import('));
+}
+
+test('login shell does not statically import export, preview, admin, or chart engines', () => {
+  const app = staticImports('./App.tsx').join('\n');
+  for (const banned of [
+    'docxRenderer',
+    'xlsxRenderer',
+    'downloadDocx',
+    'FilePreviewPanel',
+    'AdminConsoleView',
+    'ChatExportModal',
+    'BlockEditorModal',
+    "from 'docx'",
+    "from 'mermaid'",
+    "from 'xlsx'",
+  ]) {
+    assert.equal(app.includes(banned), false, `App.tsx static import still mentions ${banned}`);
+  }
+  const appText = readFileSync(new URL('./App.tsx', import.meta.url), 'utf8');
+  assert.match(appText, /import\('\.\/engine\/docxRenderer'\)/);
+  assert.match(appText, /import\('\.\/engine\/xlsxRenderer'\)/);
+  assert.match(appText, /import\('\.\/features\/replyExport\/downloadDocx'\)/);
+
+  const blocks = staticImports('./components/doc/BlockRenderer.tsx').join('\n');
+  assert.equal(blocks.includes('MermaidBlockView'), false);
+  assert.equal(blocks.includes('MathBlockView'), false);
+
+  const markdownDownload = readFileSync(new URL('./features/replyExport/download.ts', import.meta.url), 'utf8');
+  assert.equal(markdownDownload.includes("from 'docx'"), false);
+});