Register the audit workspace builtin so its entry is reachable

Why: buildWorkspaceEntries pushed only BUILTINS[0] (agents); the U4
rdm-audit workspace was declared but never ranked, so no user could
open the trace/audit workspace from the sidebar.

Evidence: vitest workspaces.test.ts 4/4 (updated expectations plus a
new overflow-truncation case); full browser run in scripts/e2e.sh.

Impact: sidebar gains the second builtin tool; server-declared
workspaces keep their shortcut precedence.

Refs: U4 (Dev #368) regression; task feature/rdm-e2e-acceptance.

e2e/rdm-audit.playwright.ts

@@ -36,14 +36,13 @@ async function login(page: Page) {
     await page.getByPlaceholder('初始密码或常用密码').fill(PASSWORD2)
     await page.getByRole('button', { name: '登录', exact: true }).click()
   }
-  // 登录成功后左侧体系工具栏出现「追溯审计」入口。
-  await expect(page.locator('button[title^="追溯审计"]')).toBeVisible({ timeout: 15_000 })
+  // 登录成功后侧栏体系工具出现「追溯审计」入口。
+  await expect(page.locator('.tsb-tool', { hasText: '追溯审计' })).toBeVisible({ timeout: 15_000 })
 }
 
 async function openAudit(page: Page) {
-  // 左栏默认展开且展开态无体系工具入口：先收起（⌘B 按钮进入 icon 轨）。
-  await page.locator('button[title="收起侧栏（⌘B）"]').click()
-  await page.locator('button[title^="追溯审计"]').click()
+  // 展开态侧栏底部的体系工具条（tsb-tool，name=标题）。
+  await page.locator('.tsb-tool', { hasText: '追溯审计' }).click()
   await expect(page.getByText('追溯审计').first()).toBeVisible()
   await expect(page.locator('.rdm-audit-project')).toBeVisible()
 }

src/workspaces.ts

@@ -57,6 +57,7 @@ export function buildWorkspaceEntries(server: WorkspaceSource[]): WorkspaceEntry
     return 99
   }
   ranked.push({ rank: takeFree(1), entry: BUILTINS[0] })
+  ranked.push({ rank: takeFree(2), entry: BUILTINS[1] })
   for (const entry of unranked) ranked.push({ rank: takeFree(9), entry })
   return ranked
     .filter(item => item.rank <= 9)

test/workspaces.test.ts

@@ -1,19 +1,20 @@
 import { describe, expect, it } from 'vitest'
 import { buildWorkspaceEntries } from '../src/workspaces'
 
-// 三栏工作台（2026-10-11）：文件浏览并入第三栏「文件」入口，体系工具只补「代理」。
+// 三栏工作台（2026-10-11）：文件浏览并入第三栏「文件」入口；体系工具内置
+// 「代理」与「追溯审计」（U4 修复：第二个 builtin 此前未入列，入口不可达）。
 describe('buildWorkspaceEntries', () => {
-  it('没有领域插件时，代理补在 ⌘1', () => {
+  it('没有领域插件时，代理补 ⌘1、追溯审计补 ⌘2', () => {
     const entries = buildWorkspaceEntries([])
-    expect(entries.map(e => `${e.shortcut} ${e.title}`)).toEqual(['⌘1 代理'])
+    expect(entries.map(e => `${e.shortcut} ${e.title}`)).toEqual(['⌘1 代理', '⌘2 追溯审计'])
   })
 
   it('声明了 shortcut 的工作区占住该位，内置工具让位', () => {
     const entries = buildWorkspaceEntries([
       { id: 'trace', title: '追溯网', shortcut: '1' },
     ])
-    expect(entries.map(e => e.title)).toEqual(['追溯网', '代理'])
-    expect(entries.map(e => e.shortcut)).toEqual(['⌘1', '⌘2'])
+    expect(entries.map(e => e.title)).toEqual(['追溯网', '代理', '追溯审计'])
+    expect(entries.map(e => e.shortcut)).toEqual(['⌘1', '⌘2', '⌘3'])
     expect(entries[0].key).toBe('ws:trace')
   })
 
@@ -21,6 +22,15 @@ describe('buildWorkspaceEntries', () => {
     const entries = buildWorkspaceEntries([
       { id: 'mem', title: '记忆库' },
     ])
-    expect(entries.map(e => e.title)).toEqual(['代理', '记忆库'])
+    expect(entries.map(e => e.title)).toEqual(['代理', '追溯审计', '记忆库'])
+  })
+
+  it('九位占满时低序内置保留，溢出项截断', () => {
+    const server = Array.from({ length: 8 }, (_, i) => ({ id: `w${i}`, title: `w${i}`, shortcut: String(i + 1) }))
+    const entries = buildWorkspaceEntries(server)
+    // ⌘1–8 被声明占住；代理取 ⌘9；追溯审计溢出截断（slice 0,9）。
+    expect(entries.filter(e => e.key.startsWith('ws:'))).toHaveLength(8)
+    expect(entries.map(e => e.title)).toContain('代理')
+    expect(entries.map(e => e.title)).not.toContain('追溯审计')
   })
 })