新增全局协作台账并统一工作台管理界面

新增与项目平级的协作台账，提供空白模板、独立账号授权和在线编辑。
复用共享库的访问权限与历史版本界面，拆分信息维护入口并统一工作台卡片样式。
补充在线文档字体构建支持、数据库表结构升级和回归测试。
不包含本地台账内容、账号授权记录或历史文件迁移数据。

frontend/src/router/index.ts

@@ -121,6 +121,18 @@ const routes: RouteRecordRaw[] = [
     component: WebWorkbenchEntry,
     meta: { title: "工作台入口" },
   },
+  {
+    path: "/ledgers/:fileId",
+    name: "LedgerWorkspace",
+    component: CollaborationWorkspace,
+    meta: { title: "协作台账", ledgerWorkspace: true },
+  },
+  {
+    path: "/ledgers/:fileId/revisions/:id/preview",
+    name: "LedgerRevisionPreview",
+    component: OfficePreviewWorkspace,
+    meta: { title: "台账历史版本预览", ledgerWorkspace: true },
+  },
   {
     path: DESKTOP_PROJECT_ENTRY_PATH,
     name: "DesktopProjectEntry",
@@ -641,7 +653,7 @@ router.beforeEach(async (to, _from, next) => {
     studyStore.rememberCurrentStudyForUser(auth.user.email);
   }
 
-  if (token && isWorkbenchEntryPath(to.path) && studyStore.currentStudy) {
+  if (token && (isWorkbenchEntryPath(to.path) || to.meta.ledgerWorkspace) && studyStore.currentStudy) {
     studyStore.clearCurrentStudy();
   }