fix: PagePurpose props on ground-truth and regression pages

Both pages passed `moduleId` which is not a valid prop for PagePurpose.
The component expects explicit title/purpose/audience — calling
audience.join() on undefined caused the client-side crash.

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

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

@@ -273,7 +273,20 @@ export default function GroundTruthReviewPage() {
   return (
     <AIToolsSidebarResponsive>
       <div className="max-w-[1600px] mx-auto p-4 space-y-4">
-        <PagePurpose moduleId="ocr-ground-truth" />
+        <PagePurpose
+          title="Ground Truth Review"
+          purpose="Effiziente Massenpruefung von OCR-Sessions: Bild und Grid nebeneinander pruefen, Fehler inline korrigieren, Sessions als Ground Truth markieren."
+          audience={['Entwickler', 'QA']}
+          defaultCollapsed
+          architecture={{
+            services: ['klausur-service (FastAPI, Port 8086)'],
+            databases: ['PostgreSQL (ocr_pipeline_sessions)'],
+          }}
+          relatedPages={[
+            { name: 'OCR Pipeline', href: '/ai/ocr-pipeline', description: 'OCR-Pipeline ausfuehren' },
+            { name: 'OCR Regression', href: '/ai/ocr-regression', description: 'Regressions-Tests' },
+          ]}
+        />
 
         {/* Progress Bar */}
         <div className="bg-white rounded-lg border border-slate-200 p-4">

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

@@ -167,7 +167,20 @@ export default function OCRRegressionPage() {
   return (
     <AIToolsSidebarResponsive>
       <div className="max-w-7xl mx-auto p-6 space-y-6">
-        <PagePurpose moduleId="ocr-regression" />
+        <PagePurpose
+          title="OCR Regression Tests"
+          purpose="Automatische Regressions-Tests fuer die OCR-Pipeline: Ground-Truth Sessions neu auswerten und gegen Referenz-Ergebnisse vergleichen."
+          audience={['Entwickler', 'QA']}
+          defaultCollapsed
+          architecture={{
+            services: ['klausur-service (FastAPI, Port 8086)'],
+            databases: ['PostgreSQL (regression_runs, ocr_pipeline_sessions)'],
+          }}
+          relatedPages={[
+            { name: 'OCR Pipeline', href: '/ai/ocr-pipeline', description: 'OCR-Pipeline ausfuehren' },
+            { name: 'Ground Truth Review', href: '/ai/ocr-ground-truth', description: 'Sessions pruefen & markieren' },
+          ]}
+        />
 
         {/* Header + Run Button */}
         <div className="flex items-center justify-between">