fix: ground-truth crash on col_type + remove AIToolsSidebarResponsive from model-management

- Ground-truth: zone.columns use 'label' not 'col_type' — calling
  .replace() on undefined crashed the page after grid data loaded
- Model-management: same AIToolsSidebarResponsive wrapper bug as the
  other pages — does not render children

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

admin-lehrer/app/(admin)/ai/model-management/page.tsx

@@ -9,7 +9,6 @@
 
 import { useState, useEffect, useCallback } from 'react'
 import { PagePurpose } from '@/components/common/PagePurpose'
-import { AIToolsSidebarResponsive } from '@/components/ai/AIToolsSidebar'
 
 const KLAUSUR_API = '/klausur-api'
 
@@ -231,7 +230,7 @@ export default function ModelManagementPage() {
   ]
 
   return (
-    <AIToolsSidebarResponsive>
+    <div className="space-y-6">
       <div className="max-w-7xl mx-auto p-6 space-y-6">
         <PagePurpose
           title="Model Management"
@@ -545,6 +544,6 @@ export default function ModelManagementPage() {
           </div>
         )}
       </div>
-    </AIToolsSidebarResponsive>
+    </div>
   )
 }

admin-lehrer/app/(admin)/ai/ocr-ground-truth/page.tsx

@@ -466,7 +466,7 @@ export default function GroundTruthReviewPage() {
                           Zone {zi + 1} ({zone.zone_type})
                           {zone.columns?.length > 0 && (
                             <span className="ml-2">
-                              {zone.columns.map(c => c.col_type.replace('column_', '')).join(' | ')}
+                              {zone.columns.map((c: any) => (c.label || c.col_type || '').replace('column_', '')).join(' | ')}
                             </span>
                           )}
                         </div>