fix: Restore all files lost during destructive rebase

A previous `git pull --rebase origin main` dropped 177 local commits,
losing 3400+ files across admin-v2, backend, studio-v2, website,
klausur-service, and many other services. The partial restore attempt
(660295e2) only recovered some files.

This commit restores all missing files from pre-rebase ref 98933f5e
while preserving post-rebase additions (night-scheduler, night-mode UI,
NightModeWidget dashboard integration).

Restored features include:
- AI Module Sidebar (FAB), OCR Labeling, OCR Compare
- GPU Dashboard, RAG Pipeline, Magic Help
- Klausur-Korrektur (8 files), Abitur-Archiv (5+ files)
- Companion, Zeugnisse-Crawler, Screen Flow
- Full backend, studio-v2, website, klausur-service
- All compliance SDKs, agent-core, voice-service
- CI/CD configs, documentation, scripts

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

website/app/lehrer/klausur-korrektur/[klausurId]/fairness/page.tsx

@@ -0,0 +1,497 @@
+'use client'
+
+/**
+ * Fairness-Dashboard
+ *
+ * Visualizes grading consistency and identifies outliers for review.
+ * Features:
+ * - Grade distribution histogram
+ * - Criteria heatmap
+ * - Outlier list with quick navigation
+ * - Fairness score gauge
+ */
+
+import { useState, useEffect, useCallback } from 'react'
+import { useParams, useRouter } from 'next/navigation'
+import AdminLayout from '@/components/admin/AdminLayout'
+import Link from 'next/link'
+
+const API_BASE = process.env.NEXT_PUBLIC_KLAUSUR_SERVICE_URL || 'http://localhost:8086'
+
+// Grade labels
+const GRADE_LABELS: Record<number, string> = {
+  15: '1+', 14: '1', 13: '1-', 12: '2+', 11: '2', 10: '2-',
+  9: '3+', 8: '3', 7: '3-', 6: '4+', 5: '4', 4: '4-',
+  3: '5+', 2: '5', 1: '5-', 0: '6'
+}
+
+// Criterion colors
+const CRITERION_COLORS: Record<string, string> = {
+  rechtschreibung: '#dc2626',
+  grammatik: '#2563eb',
+  inhalt: '#16a34a',
+  struktur: '#9333ea',
+  stil: '#ea580c',
+}
+
+interface FairnessData {
+  klausur_id: string
+  students_count: number
+  graded_count: number
+  statistics: {
+    average_grade: number
+    average_raw_points: number
+    min_grade: number
+    max_grade: number
+    spread: number
+    standard_deviation: number
+  }
+  criteria_breakdown: Record<string, {
+    average: number
+    min: number
+    max: number
+    count: number
+  }>
+  outliers: Array<{
+    student_id: string
+    student_name: string
+    grade_points: number
+    deviation: number
+    direction: 'above' | 'below'
+  }>
+  fairness_score: number
+  warnings: string[]
+  recommendation: string
+}
+
+interface Klausur {
+  id: string
+  title: string
+  subject: string
+  students: Array<{
+    id: string
+    student_name: string
+    anonym_id: string
+    grade_points: number
+    criteria_scores: Record<string, { score: number }>
+  }>
+}
+
+export default function FairnessDashboardPage() {
+  const params = useParams()
+  const router = useRouter()
+  const klausurId = params.klausurId as string
+
+  const [klausur, setKlausur] = useState<Klausur | null>(null)
+  const [fairnessData, setFairnessData] = useState<FairnessData | null>(null)
+  const [loading, setLoading] = useState(true)
+  const [error, setError] = useState<string | null>(null)
+
+  // Fetch data
+  const fetchData = useCallback(async () => {
+    try {
+      setLoading(true)
+
+      // Fetch klausur
+      const klausurRes = await fetch(`${API_BASE}/api/v1/klausuren/${klausurId}`)
+      if (klausurRes.ok) {
+        setKlausur(await klausurRes.json())
+      }
+
+      // Fetch fairness analysis
+      const fairnessRes = await fetch(`${API_BASE}/api/v1/klausuren/${klausurId}/fairness`)
+      if (fairnessRes.ok) {
+        setFairnessData(await fairnessRes.json())
+      } else {
+        const errData = await fairnessRes.json()
+        setError(errData.detail || 'Fehler beim Laden der Fairness-Analyse')
+      }
+
+      setError(null)
+    } catch (err) {
+      console.error('Failed to fetch data:', err)
+      setError('Fehler beim Laden der Daten')
+    } finally {
+      setLoading(false)
+    }
+  }, [klausurId])
+
+  useEffect(() => {
+    fetchData()
+  }, [fetchData])
+
+  // Calculate grade distribution for histogram
+  const getGradeDistribution = () => {
+    if (!klausur?.students) return []
+
+    const distribution: Record<number, number> = {}
+    for (let i = 0; i <= 15; i++) {
+      distribution[i] = 0
+    }
+
+    klausur.students.forEach(s => {
+      if (s.grade_points >= 0 && s.grade_points <= 15) {
+        distribution[s.grade_points]++
+      }
+    })
+
+    return Object.entries(distribution).map(([grade, count]) => ({
+      grade: parseInt(grade),
+      count,
+      label: GRADE_LABELS[parseInt(grade)] || grade
+    }))
+  }
+
+  const gradeDistribution = getGradeDistribution()
+  const maxCount = Math.max(...gradeDistribution.map(d => d.count), 1)
+
+  if (loading) {
+    return (
+      <AdminLayout title="Lade Fairness-Analyse..." description="">
+        <div className="flex items-center justify-center h-[calc(100vh-200px)]">
+          <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-primary-600"></div>
+        </div>
+      </AdminLayout>
+    )
+  }
+
+  return (
+    <AdminLayout
+      title="Fairness-Analyse"
+      description={klausur?.title || ''}
+    >
+      {/* Header */}
+      <div className="bg-white border-b border-slate-200 -mx-6 -mt-6 px-6 py-4 mb-6">
+        <div className="flex items-center justify-between">
+          <Link
+            href={`/lehrer/klausur-korrektur/${klausurId}`}
+            className="text-primary-600 hover:text-primary-800 flex items-center gap-1 text-sm"
+          >
+            <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M15 19l-7-7 7-7" />
+            </svg>
+            Zurueck zur Klausur
+          </Link>
+
+          <div className="text-sm text-slate-500">
+            {fairnessData?.graded_count || 0} von {fairnessData?.students_count || 0} Arbeiten bewertet
+          </div>
+        </div>
+      </div>
+
+      {/* Error display */}
+      {error && (
+        <div className="mb-6 p-4 bg-red-50 border border-red-200 rounded-lg text-red-800">
+          {error}
+        </div>
+      )}
+
+      {fairnessData && (
+        <div className="space-y-6">
+          {/* Top Row: Fairness Score + Statistics */}
+          <div className="grid grid-cols-1 md:grid-cols-3 gap-6">
+            {/* Fairness Score Gauge */}
+            <div className="bg-white rounded-lg border border-slate-200 p-6">
+              <h3 className="text-sm font-medium text-slate-500 mb-4">Fairness-Score</h3>
+              <div className="flex items-center justify-center">
+                <div className="relative w-32 h-32">
+                  {/* Background circle */}
+                  <svg className="w-32 h-32 transform -rotate-90">
+                    <circle
+                      cx="64"
+                      cy="64"
+                      r="56"
+                      fill="none"
+                      stroke="#e2e8f0"
+                      strokeWidth="12"
+                    />
+                    {/* Progress circle */}
+                    <circle
+                      cx="64"
+                      cy="64"
+                      r="56"
+                      fill="none"
+                      stroke={
+                        fairnessData.fairness_score >= 70 ? '#16a34a' :
+                        fairnessData.fairness_score >= 40 ? '#eab308' : '#dc2626'
+                      }
+                      strokeWidth="12"
+                      strokeLinecap="round"
+                      strokeDasharray={`${(fairnessData.fairness_score / 100) * 352} 352`}
+                    />
+                  </svg>
+                  {/* Score text */}
+                  <div className="absolute inset-0 flex flex-col items-center justify-center">
+                    <span className="text-3xl font-bold">{fairnessData.fairness_score}</span>
+                    <span className="text-xs text-slate-500">von 100</span>
+                  </div>
+                </div>
+              </div>
+              <div className={`mt-4 text-center text-sm font-medium ${
+                fairnessData.fairness_score >= 70 ? 'text-green-600' :
+                fairnessData.fairness_score >= 40 ? 'text-yellow-600' : 'text-red-600'
+              }`}>
+                {fairnessData.recommendation}
+              </div>
+            </div>
+
+            {/* Statistics */}
+            <div className="bg-white rounded-lg border border-slate-200 p-6">
+              <h3 className="text-sm font-medium text-slate-500 mb-4">Statistik</h3>
+              <div className="space-y-3">
+                <div className="flex justify-between">
+                  <span className="text-slate-600">Durchschnitt</span>
+                  <span className="font-semibold">
+                    {fairnessData.statistics.average_grade} P ({GRADE_LABELS[Math.round(fairnessData.statistics.average_grade)]})
+                  </span>
+                </div>
+                <div className="flex justify-between">
+                  <span className="text-slate-600">Minimum</span>
+                  <span className="font-semibold">
+                    {fairnessData.statistics.min_grade} P ({GRADE_LABELS[fairnessData.statistics.min_grade]})
+                  </span>
+                </div>
+                <div className="flex justify-between">
+                  <span className="text-slate-600">Maximum</span>
+                  <span className="font-semibold">
+                    {fairnessData.statistics.max_grade} P ({GRADE_LABELS[fairnessData.statistics.max_grade]})
+                  </span>
+                </div>
+                <div className="flex justify-between">
+                  <span className="text-slate-600">Spreizung</span>
+                  <span className="font-semibold">{fairnessData.statistics.spread} P</span>
+                </div>
+                <div className="flex justify-between">
+                  <span className="text-slate-600">Standardabweichung</span>
+                  <span className="font-semibold">{fairnessData.statistics.standard_deviation}</span>
+                </div>
+              </div>
+            </div>
+
+            {/* Warnings */}
+            <div className="bg-white rounded-lg border border-slate-200 p-6">
+              <h3 className="text-sm font-medium text-slate-500 mb-4">Hinweise</h3>
+              {fairnessData.warnings.length > 0 ? (
+                <div className="space-y-2">
+                  {fairnessData.warnings.map((warning, i) => (
+                    <div key={i} className="flex items-start gap-2 text-sm">
+                      <svg className="w-5 h-5 text-amber-500 flex-shrink-0 mt-0.5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                        <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 9v2m0 4h.01m-6.938 4h13.856c1.54 0 2.502-1.667 1.732-3L13.732 4c-.77-1.333-2.694-1.333-3.464 0L3.34 16c-.77 1.333.192 3 1.732 3z" />
+                      </svg>
+                      <span className="text-slate-700">{warning}</span>
+                    </div>
+                  ))}
+                </div>
+              ) : (
+                <div className="flex items-center gap-2 text-green-600">
+                  <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                    <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
+                  </svg>
+                  <span className="text-sm">Keine Auffaelligkeiten erkannt</span>
+                </div>
+              )}
+            </div>
+          </div>
+
+          {/* Grade Distribution Histogram */}
+          <div className="bg-white rounded-lg border border-slate-200 p-6">
+            <h3 className="text-sm font-medium text-slate-500 mb-4">Notenverteilung</h3>
+            <div className="flex items-end gap-1 h-48">
+              {gradeDistribution.map(({ grade, count, label }) => (
+                <div key={grade} className="flex-1 flex flex-col items-center">
+                  <div
+                    className={`w-full rounded-t transition-all ${
+                      count > 0 ? 'bg-primary-500' : 'bg-slate-200'
+                    }`}
+                    style={{ height: `${(count / maxCount) * 160}px`, minHeight: count > 0 ? '8px' : '2px' }}
+                    title={`${count} Arbeiten`}
+                  />
+                  <div className="text-xs text-slate-500 mt-1 transform -rotate-45 origin-top-left w-6 text-center">
+                    {label}
+                  </div>
+                  {count > 0 && (
+                    <div className="text-xs font-medium text-slate-700 mt-1">{count}</div>
+                  )}
+                </div>
+              ))}
+            </div>
+            <div className="flex justify-between text-xs text-slate-400 mt-6">
+              <span>6 (0 Punkte)</span>
+              <span>1+ (15 Punkte)</span>
+            </div>
+          </div>
+
+          {/* Criteria Breakdown Heatmap */}
+          <div className="bg-white rounded-lg border border-slate-200 p-6">
+            <h3 className="text-sm font-medium text-slate-500 mb-4">Kriterien-Vergleich</h3>
+            <div className="space-y-3">
+              {Object.entries(fairnessData.criteria_breakdown).map(([criterion, data]) => {
+                const color = CRITERION_COLORS[criterion] || '#6b7280'
+                const range = data.max - data.min
+
+                return (
+                  <div key={criterion} className="flex items-center gap-4">
+                    <div className="w-32 flex items-center gap-2">
+                      <div className="w-3 h-3 rounded-full" style={{ backgroundColor: color }} />
+                      <span className="text-sm font-medium capitalize">{criterion}</span>
+                    </div>
+                    <div className="flex-1">
+                      <div className="relative h-6 bg-slate-100 rounded-full overflow-hidden">
+                        {/* Range bar */}
+                        <div
+                          className="absolute h-full opacity-30"
+                          style={{
+                            backgroundColor: color,
+                            left: `${data.min}%`,
+                            width: `${range}%`
+                          }}
+                        />
+                        {/* Average marker */}
+                        <div
+                          className="absolute top-0 bottom-0 w-1 rounded"
+                          style={{
+                            backgroundColor: color,
+                            left: `${data.average}%`
+                          }}
+                        />
+                      </div>
+                    </div>
+                    <div className="w-24 text-right">
+                      <span className="text-sm font-semibold">{data.average}%</span>
+                      <span className="text-xs text-slate-400 ml-1">avg</span>
+                    </div>
+                    <div className="w-20 text-right text-xs text-slate-500">
+                      {data.min}% - {data.max}%
+                    </div>
+                  </div>
+                )
+              })}
+            </div>
+          </div>
+
+          {/* Outliers List */}
+          {fairnessData.outliers.length > 0 && (
+            <div className="bg-white rounded-lg border border-slate-200 p-6">
+              <h3 className="text-sm font-medium text-slate-500 mb-4">
+                Ausreisser ({fairnessData.outliers.length})
+              </h3>
+              <div className="space-y-2">
+                {fairnessData.outliers.map((outlier) => (
+                  <div
+                    key={outlier.student_id}
+                    className={`flex items-center justify-between p-3 rounded-lg border ${
+                      outlier.direction === 'above'
+                        ? 'bg-green-50 border-green-200'
+                        : 'bg-red-50 border-red-200'
+                    }`}
+                  >
+                    <div className="flex items-center gap-3">
+                      <div className={`w-8 h-8 rounded-full flex items-center justify-center text-white font-bold ${
+                        outlier.direction === 'above' ? 'bg-green-500' : 'bg-red-500'
+                      }`}>
+                        {outlier.direction === 'above' ? '↑' : '↓'}
+                      </div>
+                      <div>
+                        <div className="font-medium">{outlier.student_name}</div>
+                        <div className="text-sm text-slate-500">
+                          {outlier.grade_points} Punkte ({GRADE_LABELS[outlier.grade_points]}) -
+                          Abweichung: {outlier.deviation} Punkte {outlier.direction === 'above' ? 'ueber' : 'unter'} Durchschnitt
+                        </div>
+                      </div>
+                    </div>
+                    <Link
+                      href={`/lehrer/klausur-korrektur/${klausurId}/${outlier.student_id}`}
+                      className="px-4 py-2 bg-white border border-slate-300 rounded-lg text-sm hover:bg-slate-50 flex items-center gap-2"
+                    >
+                      <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                        <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M15 12a3 3 0 11-6 0 3 3 0 016 0z" />
+                        <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M2.458 12C3.732 7.943 7.523 5 12 5c4.478 0 8.268 2.943 9.542 7-1.274 4.057-5.064 7-9.542 7-4.477 0-8.268-2.943-9.542-7z" />
+                      </svg>
+                      Pruefen
+                    </Link>
+                  </div>
+                ))}
+              </div>
+            </div>
+          )}
+
+          {/* All Students Table */}
+          <div className="bg-white rounded-lg border border-slate-200 p-6">
+            <h3 className="text-sm font-medium text-slate-500 mb-4">
+              Alle Arbeiten ({klausur?.students.length || 0})
+            </h3>
+            <div className="overflow-x-auto">
+              <table className="w-full text-sm">
+                <thead>
+                  <tr className="border-b border-slate-200">
+                    <th className="text-left py-2 px-3 font-medium text-slate-600">Student</th>
+                    <th className="text-center py-2 px-3 font-medium text-slate-600">Note</th>
+                    <th className="text-center py-2 px-3 font-medium text-slate-600">RS</th>
+                    <th className="text-center py-2 px-3 font-medium text-slate-600">Gram</th>
+                    <th className="text-center py-2 px-3 font-medium text-slate-600">Inhalt</th>
+                    <th className="text-center py-2 px-3 font-medium text-slate-600">Struktur</th>
+                    <th className="text-center py-2 px-3 font-medium text-slate-600">Stil</th>
+                    <th className="text-right py-2 px-3 font-medium text-slate-600">Aktion</th>
+                  </tr>
+                </thead>
+                <tbody>
+                  {klausur?.students
+                    .sort((a, b) => b.grade_points - a.grade_points)
+                    .map((student) => {
+                      const isOutlier = fairnessData.outliers.some(o => o.student_id === student.id)
+                      const outlierInfo = fairnessData.outliers.find(o => o.student_id === student.id)
+
+                      return (
+                        <tr
+                          key={student.id}
+                          className={`border-b border-slate-100 ${
+                            isOutlier
+                              ? outlierInfo?.direction === 'above'
+                                ? 'bg-green-50'
+                                : 'bg-red-50'
+                              : ''
+                          }`}
+                        >
+                          <td className="py-2 px-3">
+                            <div className="font-medium">{student.anonym_id}</div>
+                          </td>
+                          <td className="py-2 px-3 text-center">
+                            <span className="font-bold">
+                              {student.grade_points} ({GRADE_LABELS[student.grade_points] || '-'})
+                            </span>
+                          </td>
+                          <td className="py-2 px-3 text-center">
+                            {student.criteria_scores?.rechtschreibung?.score ?? '-'}%
+                          </td>
+                          <td className="py-2 px-3 text-center">
+                            {student.criteria_scores?.grammatik?.score ?? '-'}%
+                          </td>
+                          <td className="py-2 px-3 text-center">
+                            {student.criteria_scores?.inhalt?.score ?? '-'}%
+                          </td>
+                          <td className="py-2 px-3 text-center">
+                            {student.criteria_scores?.struktur?.score ?? '-'}%
+                          </td>
+                          <td className="py-2 px-3 text-center">
+                            {student.criteria_scores?.stil?.score ?? '-'}%
+                          </td>
+                          <td className="py-2 px-3 text-right">
+                            <Link
+                              href={`/lehrer/klausur-korrektur/${klausurId}/${student.id}`}
+                              className="text-primary-600 hover:text-primary-800 text-sm"
+                            >
+                              Bearbeiten
+                            </Link>
+                          </td>
+                        </tr>
+                      )
+                    })}
+                </tbody>
+              </table>
+            </div>
+          </div>
+        </div>
+      )}
+    </AdminLayout>
+  )
+}

website/app/lehrer/klausur-korrektur/[klausurId]/page.tsx

@@ -0,0 +1,499 @@
+'use client'
+
+/**
+ * Klausur Detail Page - Student List
+ *
+ * Shows all student works for a specific Klausur with upload capability.
+ * Allows navigation to individual correction workspaces.
+ */
+
+import { useState, useEffect, useCallback, useRef } from 'react'
+import { useParams, useRouter } from 'next/navigation'
+import AdminLayout from '@/components/admin/AdminLayout'
+import Link from 'next/link'
+import type { Klausur, StudentWork, STATUS_COLORS, STATUS_LABELS } from '../types'
+
+const API_BASE = process.env.NEXT_PUBLIC_KLAUSUR_SERVICE_URL || 'http://localhost:8086'
+
+// Status configuration
+const statusConfig: Record<string, { color: string; label: string; bg: string }> = {
+  UPLOADED: { color: 'text-gray-600', label: 'Hochgeladen', bg: 'bg-gray-100' },
+  OCR_PROCESSING: { color: 'text-yellow-600', label: 'OCR läuft', bg: 'bg-yellow-100' },
+  OCR_COMPLETE: { color: 'text-blue-600', label: 'OCR fertig', bg: 'bg-blue-100' },
+  ANALYZING: { color: 'text-purple-600', label: 'Analyse', bg: 'bg-purple-100' },
+  FIRST_EXAMINER: { color: 'text-orange-600', label: 'Erstkorrektur', bg: 'bg-orange-100' },
+  SECOND_EXAMINER: { color: 'text-cyan-600', label: 'Zweitkorrektur', bg: 'bg-cyan-100' },
+  COMPLETED: { color: 'text-green-600', label: 'Fertig', bg: 'bg-green-100' },
+  ERROR: { color: 'text-red-600', label: 'Fehler', bg: 'bg-red-100' },
+}
+
+export default function KlausurDetailPage() {
+  const params = useParams()
+  const router = useRouter()
+  const klausurId = params.klausurId as string
+
+  const [klausur, setKlausur] = useState<Klausur | null>(null)
+  const [students, setStudents] = useState<StudentWork[]>([])
+  const [loading, setLoading] = useState(true)
+  const [error, setError] = useState<string | null>(null)
+  const [uploading, setUploading] = useState(false)
+  const [uploadProgress, setUploadProgress] = useState(0)
+  const [exporting, setExporting] = useState(false)
+  const fileInputRef = useRef<HTMLInputElement>(null)
+
+  // Fetch Klausur details
+  const fetchKlausur = useCallback(async () => {
+    try {
+      const res = await fetch(`${API_BASE}/api/v1/klausuren/${klausurId}`)
+      if (res.ok) {
+        const data = await res.json()
+        setKlausur(data)
+      } else if (res.status === 404) {
+        setError('Klausur nicht gefunden')
+      }
+    } catch (err) {
+      console.error('Failed to fetch klausur:', err)
+      setError('Verbindung fehlgeschlagen')
+    }
+  }, [klausurId])
+
+  // Fetch students
+  const fetchStudents = useCallback(async () => {
+    try {
+      setLoading(true)
+      const res = await fetch(`${API_BASE}/api/v1/klausuren/${klausurId}/students`)
+      if (res.ok) {
+        const data = await res.json()
+        setStudents(Array.isArray(data) ? data : data.students || [])
+        setError(null)
+      }
+    } catch (err) {
+      console.error('Failed to fetch students:', err)
+      setError('Fehler beim Laden der Arbeiten')
+    } finally {
+      setLoading(false)
+    }
+  }, [klausurId])
+
+  useEffect(() => {
+    fetchKlausur()
+    fetchStudents()
+  }, [fetchKlausur, fetchStudents])
+
+  // PDF Export functions
+  const exportOverviewPDF = async () => {
+    try {
+      setExporting(true)
+      const res = await fetch(`${API_BASE}/api/v1/klausuren/${klausurId}/export/overview`)
+      if (res.ok) {
+        const blob = await res.blob()
+        const url = window.URL.createObjectURL(blob)
+        const a = document.createElement('a')
+        a.href = url
+        a.download = `Notenuebersicht_${klausur?.title?.replace(/\s+/g, '_') || 'Klausur'}_${new Date().toISOString().split('T')[0]}.pdf`
+        document.body.appendChild(a)
+        a.click()
+        document.body.removeChild(a)
+        window.URL.revokeObjectURL(url)
+      } else {
+        setError('Fehler beim PDF-Export')
+      }
+    } catch (err) {
+      console.error('Failed to export overview PDF:', err)
+      setError('Fehler beim PDF-Export')
+    } finally {
+      setExporting(false)
+    }
+  }
+
+  const exportAllGutachtenPDF = async () => {
+    try {
+      setExporting(true)
+      const res = await fetch(`${API_BASE}/api/v1/klausuren/${klausurId}/export/all-gutachten`)
+      if (res.ok) {
+        const blob = await res.blob()
+        const url = window.URL.createObjectURL(blob)
+        const a = document.createElement('a')
+        a.href = url
+        a.download = `Alle_Gutachten_${klausur?.title?.replace(/\s+/g, '_') || 'Klausur'}_${new Date().toISOString().split('T')[0]}.pdf`
+        document.body.appendChild(a)
+        a.click()
+        document.body.removeChild(a)
+        window.URL.revokeObjectURL(url)
+      } else {
+        setError('Fehler beim PDF-Export')
+      }
+    } catch (err) {
+      console.error('Failed to export all gutachten PDF:', err)
+      setError('Fehler beim PDF-Export')
+    } finally {
+      setExporting(false)
+    }
+  }
+
+  // Handle file upload
+  const handleFileUpload = async (e: React.ChangeEvent<HTMLInputElement>) => {
+    const files = e.target.files
+    if (!files || files.length === 0) return
+
+    setUploading(true)
+    setUploadProgress(0)
+    setError(null)
+
+    const totalFiles = files.length
+    let uploadedCount = 0
+
+    for (const file of Array.from(files)) {
+      try {
+        const formData = new FormData()
+        formData.append('file', file)
+
+        const res = await fetch(`${API_BASE}/api/v1/klausuren/${klausurId}/students`, {
+          method: 'POST',
+          body: formData,
+        })
+
+        if (!res.ok) {
+          const errorData = await res.json()
+          console.error(`Failed to upload ${file.name}:`, errorData)
+        }
+
+        uploadedCount++
+        setUploadProgress(Math.round((uploadedCount / totalFiles) * 100))
+      } catch (err) {
+        console.error(`Failed to upload ${file.name}:`, err)
+      }
+    }
+
+    setUploading(false)
+    setUploadProgress(0)
+    fetchStudents()
+
+    // Reset file input
+    if (fileInputRef.current) {
+      fileInputRef.current.value = ''
+    }
+  }
+
+  // Handle delete student work
+  const handleDeleteStudent = async (studentId: string) => {
+    if (!confirm('Studentenarbeit wirklich löschen?')) return
+
+    try {
+      const res = await fetch(`${API_BASE}/api/v1/students/${studentId}`, {
+        method: 'DELETE',
+      })
+
+      if (res.ok) {
+        setStudents(prev => prev.filter(s => s.id !== studentId))
+      } else {
+        setError('Fehler beim Löschen')
+      }
+    } catch (err) {
+      console.error('Failed to delete student:', err)
+      setError('Fehler beim Löschen')
+    }
+  }
+
+  // Get grade display
+  const getGradeDisplay = (student: StudentWork) => {
+    if (student.grade_points === undefined || student.grade_points === null) {
+      return { points: '-', label: '-' }
+    }
+    const labels: Record<number, string> = {
+      15: '1+', 14: '1', 13: '1-', 12: '2+', 11: '2', 10: '2-',
+      9: '3+', 8: '3', 7: '3-', 6: '4+', 5: '4', 4: '4-',
+      3: '5+', 2: '5', 1: '5-', 0: '6'
+    }
+    return {
+      points: student.grade_points.toString(),
+      label: labels[student.grade_points] || '-'
+    }
+  }
+
+  // Calculate statistics
+  const stats = {
+    total: students.length,
+    completed: students.filter(s => s.status === 'COMPLETED').length,
+    inProgress: students.filter(s => ['FIRST_EXAMINER', 'SECOND_EXAMINER', 'ANALYZING'].includes(s.status)).length,
+    pending: students.filter(s => ['UPLOADED', 'OCR_PROCESSING', 'OCR_COMPLETE'].includes(s.status)).length,
+    avgGrade: students.filter(s => s.grade_points !== undefined && s.grade_points !== null)
+      .reduce((sum, s, _, arr) => sum + (s.grade_points || 0) / arr.length, 0).toFixed(1),
+  }
+
+  if (loading && !klausur) {
+    return (
+      <AdminLayout title="Lädt..." description="">
+        <div className="flex items-center justify-center h-64">
+          <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-primary-600"></div>
+        </div>
+      </AdminLayout>
+    )
+  }
+
+  return (
+    <AdminLayout
+      title={klausur?.title || 'Klausur'}
+      description={`${klausur?.subject} - ${klausur?.year} | ${students.length} Arbeiten`}
+    >
+      {/* Breadcrumb */}
+      <div className="mb-4">
+        <Link
+          href="/lehrer/klausur-korrektur"
+          className="text-primary-600 hover:text-primary-800 flex items-center gap-1 text-sm"
+        >
+          <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M15 19l-7-7 7-7" />
+          </svg>
+          Zurück zur Übersicht
+        </Link>
+      </div>
+
+      {/* Error display */}
+      {error && (
+        <div className="mb-4 p-4 bg-red-50 border border-red-200 rounded-lg flex items-center gap-3">
+          <svg className="w-5 h-5 text-red-600" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 8v4m0 4h.01M21 12a9 9 0 11-18 0 9 9 0 0118 0z" />
+          </svg>
+          <span className="text-red-800">{error}</span>
+          <button onClick={() => setError(null)} className="ml-auto text-red-600 hover:text-red-800">
+            <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M6 18L18 6M6 6l12 12" />
+            </svg>
+          </button>
+        </div>
+      )}
+
+      {/* Statistics Cards */}
+      <div className="grid grid-cols-2 md:grid-cols-5 gap-4 mb-6">
+        <div className="bg-white rounded-lg border border-slate-200 p-4">
+          <div className="text-2xl font-bold text-slate-800">{stats.total}</div>
+          <div className="text-sm text-slate-500">Gesamt</div>
+        </div>
+        <div className="bg-white rounded-lg border border-slate-200 p-4">
+          <div className="text-2xl font-bold text-green-600">{stats.completed}</div>
+          <div className="text-sm text-slate-500">Fertig</div>
+        </div>
+        <div className="bg-white rounded-lg border border-slate-200 p-4">
+          <div className="text-2xl font-bold text-orange-600">{stats.inProgress}</div>
+          <div className="text-sm text-slate-500">In Arbeit</div>
+        </div>
+        <div className="bg-white rounded-lg border border-slate-200 p-4">
+          <div className="text-2xl font-bold text-gray-600">{stats.pending}</div>
+          <div className="text-sm text-slate-500">Ausstehend</div>
+        </div>
+        <div className="bg-white rounded-lg border border-slate-200 p-4">
+          <div className="text-2xl font-bold text-primary-600">{stats.avgGrade}</div>
+          <div className="text-sm text-slate-500">Ø Note</div>
+        </div>
+      </div>
+
+      {/* Fairness Analysis Button */}
+      {stats.completed >= 2 && (
+        <div className="mb-6 flex flex-wrap gap-3">
+          <Link
+            href={`/lehrer/klausur-korrektur/${klausurId}/fairness`}
+            className="inline-flex items-center gap-2 px-4 py-3 bg-gradient-to-r from-purple-600 to-indigo-600 text-white rounded-lg hover:from-purple-700 hover:to-indigo-700 transition-all shadow-sm"
+          >
+            <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 19v-6a2 2 0 00-2-2H5a2 2 0 00-2 2v6a2 2 0 002 2h2a2 2 0 002-2zm0 0V9a2 2 0 012-2h2a2 2 0 012 2v10m-6 0a2 2 0 002 2h2a2 2 0 002-2m0 0V5a2 2 0 012-2h2a2 2 0 012 2v14a2 2 0 01-2 2h-2a2 2 0 01-2-2z" />
+            </svg>
+            Fairness-Analyse oeffnen
+            <span className="text-xs bg-white/20 px-2 py-0.5 rounded-full">
+              {stats.completed} bewertet
+            </span>
+          </Link>
+
+          {/* PDF Export Buttons */}
+          <button
+            onClick={exportOverviewPDF}
+            disabled={exporting}
+            className="inline-flex items-center gap-2 px-4 py-3 bg-white border border-slate-300 text-slate-700 rounded-lg hover:bg-slate-50 transition-all shadow-sm disabled:opacity-50"
+          >
+            <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 10v6m0 0l-3-3m3 3l3-3m2 8H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" />
+            </svg>
+            {exporting ? 'Exportiere...' : 'Notenuebersicht PDF'}
+          </button>
+
+          <button
+            onClick={exportAllGutachtenPDF}
+            disabled={exporting}
+            className="inline-flex items-center gap-2 px-4 py-3 bg-white border border-slate-300 text-slate-700 rounded-lg hover:bg-slate-50 transition-all shadow-sm disabled:opacity-50"
+          >
+            <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" />
+            </svg>
+            {exporting ? 'Exportiere...' : 'Alle Gutachten PDF'}
+          </button>
+        </div>
+      )}
+
+      {/* Upload Section */}
+      <div className="bg-white rounded-lg border border-slate-200 p-6 mb-6">
+        <div className="flex items-center justify-between mb-4">
+          <div>
+            <h2 className="text-lg font-semibold text-slate-800">Studentenarbeiten hochladen</h2>
+            <p className="text-sm text-slate-500">PDF oder Bilder (JPG, PNG) der gescannten Arbeiten</p>
+          </div>
+          <input
+            ref={fileInputRef}
+            type="file"
+            multiple
+            accept=".pdf,.jpg,.jpeg,.png"
+            onChange={handleFileUpload}
+            className="hidden"
+            id="file-upload"
+          />
+          <label
+            htmlFor="file-upload"
+            className={`px-4 py-2 rounded-lg flex items-center gap-2 cursor-pointer ${
+              uploading
+                ? 'bg-gray-100 text-gray-400 cursor-not-allowed'
+                : 'bg-primary-600 text-white hover:bg-primary-700'
+            }`}
+          >
+            {uploading ? (
+              <>
+                <div className="animate-spin rounded-full h-4 w-4 border-b-2 border-white"></div>
+                {uploadProgress}%
+              </>
+            ) : (
+              <>
+                <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                  <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M4 16v1a3 3 0 003 3h10a3 3 0 003-3v-1m-4-8l-4-4m0 0L8 8m4-4v12" />
+                </svg>
+                Dateien hochladen
+              </>
+            )}
+          </label>
+        </div>
+
+        {/* Upload progress */}
+        {uploading && (
+          <div className="h-2 bg-slate-100 rounded-full overflow-hidden">
+            <div
+              className="h-full bg-primary-600 rounded-full transition-all"
+              style={{ width: `${uploadProgress}%` }}
+            />
+          </div>
+        )}
+      </div>
+
+      {/* Students List */}
+      <div className="bg-white rounded-lg border border-slate-200 overflow-hidden">
+        <div className="p-4 border-b border-slate-200">
+          <h2 className="text-lg font-semibold text-slate-800">Studentenarbeiten ({students.length})</h2>
+        </div>
+
+        {loading ? (
+          <div className="flex items-center justify-center h-32">
+            <div className="animate-spin rounded-full h-6 w-6 border-b-2 border-primary-600"></div>
+          </div>
+        ) : students.length === 0 ? (
+          <div className="p-8 text-center text-slate-500">
+            <svg className="mx-auto h-12 w-12 text-slate-300 mb-3" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" />
+            </svg>
+            <p>Noch keine Arbeiten hochgeladen</p>
+            <p className="text-sm">Laden Sie gescannte PDFs oder Bilder hoch</p>
+          </div>
+        ) : (
+          <div className="divide-y divide-slate-200">
+            {students.map((student, index) => {
+              const grade = getGradeDisplay(student)
+              const status = statusConfig[student.status] || statusConfig.UPLOADED
+
+              return (
+                <div
+                  key={student.id}
+                  className="p-4 hover:bg-slate-50 flex items-center gap-4"
+                >
+                  {/* Index */}
+                  <div className="w-8 h-8 rounded-full bg-slate-100 flex items-center justify-center text-sm font-medium text-slate-600">
+                    {index + 1}
+                  </div>
+
+                  {/* Student info */}
+                  <div className="flex-1 min-w-0">
+                    <div className="font-medium text-slate-800 truncate">
+                      {student.anonym_id || `Arbeit ${index + 1}`}
+                    </div>
+                    <div className="text-sm text-slate-500 flex items-center gap-2">
+                      <span className={`px-2 py-0.5 rounded-full text-xs ${status.bg} ${status.color}`}>
+                        {status.label}
+                      </span>
+                    </div>
+                  </div>
+
+                  {/* Grade */}
+                  <div className="text-center w-20">
+                    <div className="text-lg font-bold text-slate-800">{grade.points}</div>
+                    <div className="text-xs text-slate-500">{grade.label}</div>
+                  </div>
+
+                  {/* Progress indicator */}
+                  <div className="w-24">
+                    {student.criteria_scores && Object.keys(student.criteria_scores).length > 0 ? (
+                      <div className="flex gap-1">
+                        {['rechtschreibung', 'grammatik', 'inhalt', 'struktur', 'stil'].map(criterion => (
+                          <div
+                            key={criterion}
+                            className={`h-2 flex-1 rounded-full ${
+                              student.criteria_scores[criterion] !== undefined
+                                ? 'bg-green-500'
+                                : 'bg-slate-200'
+                            }`}
+                            title={criterion}
+                          />
+                        ))}
+                      </div>
+                    ) : (
+                      <div className="text-xs text-slate-400">Keine Bewertung</div>
+                    )}
+                  </div>
+
+                  {/* Actions */}
+                  <div className="flex items-center gap-2">
+                    <Link
+                      href={`/lehrer/klausur-korrektur/${klausurId}/${student.id}`}
+                      className="px-3 py-1.5 bg-primary-600 text-white text-sm rounded-lg hover:bg-primary-700"
+                    >
+                      Korrigieren
+                    </Link>
+                    <button
+                      onClick={() => handleDeleteStudent(student.id)}
+                      className="p-1.5 text-red-600 hover:bg-red-50 rounded-lg"
+                      title="Löschen"
+                    >
+                      <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                        <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M19 7l-.867 12.142A2 2 0 0116.138 21H7.862a2 2 0 01-1.995-1.858L5 7m5 4v6m4-6v6m1-10V4a1 1 0 00-1-1h-4a1 1 0 00-1 1v3M4 7h16" />
+                      </svg>
+                    </button>
+                  </div>
+                </div>
+              )
+            })}
+          </div>
+        )}
+      </div>
+
+      {/* Fairness Check Button */}
+      {students.filter(s => s.status === 'COMPLETED').length >= 3 && (
+        <div className="mt-6 p-4 bg-blue-50 border border-blue-200 rounded-lg">
+          <div className="flex items-center justify-between">
+            <div>
+              <h3 className="font-semibold text-blue-800">Fairness-Check verfügbar</h3>
+              <p className="text-sm text-blue-600">
+                Prüfen Sie die Bewertungen auf Konsistenz und Fairness
+              </p>
+            </div>
+            <button className="px-4 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700">
+              Fairness-Check starten
+            </button>
+          </div>
+        </div>
+      )}
+    </AdminLayout>
+  )
+}