[split-required] Split 500-1000 LOC files across all services

backend-lehrer (5 files):
- alerts_agent/db/repository.py (992 → 5), abitur_docs_api.py (956 → 3)
- teacher_dashboard_api.py (951 → 3), services/pdf_service.py (916 → 3)
- mail/mail_db.py (987 → 6)

klausur-service (5 files):
- legal_templates_ingestion.py (942 → 3), ocr_pipeline_postprocess.py (929 → 4)
- ocr_pipeline_words.py (876 → 3), ocr_pipeline_ocr_merge.py (616 → 2)
- KorrekturPage.tsx (956 → 6)

website (5 pages):
- mail (985 → 9), edu-search (958 → 8), mac-mini (950 → 7)
- ocr-labeling (946 → 7), audit-workspace (871 → 4)

studio-v2 (5 files + 1 deleted):
- page.tsx (946 → 5), MessagesContext.tsx (925 → 4)
- korrektur (914 → 6), worksheet-cleanup (899 → 6)
- useVocabWorksheet.ts (888 → 3)
- Deleted dead page-original.tsx (934 LOC)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

klausur-service/frontend/src/pages/KorrekturConstants.ts

@@ -0,0 +1,37 @@
+/**
+ * KorrekturPage Constants — grade tables, criteria definitions, types.
+ *
+ * Extracted from KorrekturPage.tsx.
+ */
+
+// Grade calculation
+export const GRADE_THRESHOLDS: Record<number, number> = {
+  15: 95, 14: 90, 13: 85, 12: 80, 11: 75, 10: 70,
+  9: 65, 8: 60, 7: 55, 6: 50, 5: 45, 4: 40,
+  3: 33, 2: 27, 1: 20, 0: 0
+}
+
+export 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'
+}
+
+export const CRITERIA = [
+  { key: 'inhalt', label: 'Inhaltliche Leistung', weight: 0.40 },
+  { key: 'struktur', label: 'Aufbau & Struktur', weight: 0.15 },
+  { key: 'stil', label: 'Ausdruck & Stil', weight: 0.15 },
+  { key: 'grammatik', label: 'Grammatik', weight: 0.15 },
+  { key: 'rechtschreibung', label: 'Rechtschreibung', weight: 0.15 }
+] as const
+
+export type WizardStep = 'korrektur' | 'bewertung' | 'gutachten'
+
+export function calculateGradePoints(percentage: number): number {
+  for (const [points, threshold] of Object.entries(GRADE_THRESHOLDS).sort((a, b) => Number(b[0]) - Number(a[0]))) {
+    if (percentage >= threshold) {
+      return Number(points)
+    }
+  }
+  return 0
+}