feat: show system update history as timeline

frontend/e2e/system-update.e2e.ts

@@ -138,6 +138,7 @@ async function installFixture(
       beforeJson: null,
       afterJson: JSON.stringify({
         targetVersion,
+        ...(actionCode === 'SYSTEM_UPDATE_CHECK' ? { releaseNotes: 'Preview update' } : {}),
         ...(actionCode === 'SYSTEM_UPDATE_SUCCEEDED' ? { state: 'SUCCEEDED' } : {}),
       }),
       occurredAt: '2026-08-16T00:02:00Z',
@@ -415,9 +416,17 @@ test('successful installation starts the ten-second automatic refresh countdown'
     timeout: 5_000,
   });
   const historyPanel = page.locator('.history-panel');
-  const completedRow = historyPanel.locator('tr').filter({ hasText: '更新完成' });
-  await expect(completedRow).toContainText('1.0.0-preview.2');
-  await expect(completedRow).toContainText('新版本已通过健康检查');
+  const timelineItem = historyPanel.locator('.update-timeline__item[data-version="1.0.0-preview.2"]');
+  await expect(timelineItem).toHaveCount(1);
+  await expect(timelineItem).toContainText('更新完成');
+  await expect(timelineItem).toContainText('新版本已通过健康检查');
+  await expect(timelineItem).toContainText('Preview update');
+  await timelineItem.getByRole('button', { name: '查看完整记录', exact: true }).click();
+  const historyDialog = page.getByRole('dialog', { name: '更新日志详情' });
+  await expect(historyDialog).toContainText('获取版本');
+  await expect(historyDialog).toContainText('下载更新包');
+  await expect(historyDialog).toContainText('立即更新并重启');
+  await expect(historyDialog).toContainText('更新完成');
 });
 
 test('reloading during installation resumes polling and starts the refresh countdown', async ({ page }) => {