fix(ui): restore Tests tab, fix renderMarkdown undefined error

- Restore Tests tab in navigation (was removed by mistake)
- Fix renderMarkdown ReferenceError by restoring the callback (raw=false always)
- Keep Copy MD button and removal of raw-md/collapse toggles

Assisted-by: GLM-5.1 via Crush <crush@charm.land>

web/src/components/App.jsx

@@ -1,5 +1,5 @@
 import { useState, useEffect, useCallback, useMemo, useRef } from 'react'
-import { LayoutDashboard, Sparkles, Terminal, Settings } from 'lucide-react'
+import { LayoutDashboard, Sparkles, Terminal, Settings, TestTube2 } from 'lucide-react'
 import api from '../api/client'
 import { getTheme, applyTheme } from '../themes'
 import { useI18n } from '../i18n'
@@ -7,6 +7,7 @@ import Dashboard from './Dashboard'
 import Studio from './Studio'
 import Shell from './Shell'
 import Config from './Config'
+import Tests from './Tests'
 import OnboardingWizard from './OnboardingWizard'
 
 export default function App() {
@@ -24,6 +25,7 @@ export default function App() {
     { id: 'dash', label: t('tabs.dashboard'), icon: <LayoutDashboard size={15} /> },
     { id: 'studio', label: t('tabs.studio'), icon: <Sparkles size={15} /> },
     { id: 'shell', label: t('tabs.shell'), icon: <Terminal size={15} /> },
+    { id: 'tests', label: 'Tests', icon: <TestTube2 size={15} /> },
     { id: 'config', label: t('tabs.config'), icon: <Settings size={15} /> },
   ], [t])
 
@@ -54,7 +56,8 @@ export default function App() {
         Digit1: 'dash',
         Digit2: 'studio',
         Digit3: 'shell',
-        Digit4: 'config',
+        Digit4: 'tests',
+        Digit5: 'config',
       }
       if (map[e.code]) {
         e.preventDefault()
@@ -131,6 +134,7 @@ export default function App() {
         <div className={activeTab === 'dash' ? '' : 'tab-hidden'}><Dashboard api={api} refreshRef={dashRefreshRef} /></div>
         <div className={activeTab === 'studio' ? '' : 'tab-hidden'}><Studio api={api} /></div>
         <div className={activeTab === 'shell' ? '' : 'tab-hidden'}><Shell api={api} isSudo={isSudo} /></div>
+        <div className={activeTab === 'tests' ? '' : 'tab-hidden'}><Tests api={api} /></div>
         <div className={activeTab === 'config' ? '' : 'tab-hidden'}><Config api={api} /></div>
       </main>
 

web/src/components/Studio.jsx

@@ -285,8 +285,9 @@ function FeedItem({ msg, activeAgents, onModeChange }) {
 
   const timeStr = msg.time ? new Date(msg.time).toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' }) : ''
 
-
+  const renderMarkdown = useCallback((content) => {
-
+    return <MarkdownContent content={content} raw={false} />
+  }, [])
   let parsedToolCalls = null
   let parsedToolResults = null
   let parsedSegments = null