[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>

studio-v2/app/worksheet-cleanup/_components/ProgressRing.tsx

@@ -0,0 +1,47 @@
+'use client'
+
+interface ProgressRingProps {
+  progress: number
+  size?: number
+  strokeWidth?: number
+  label: string
+  value: string
+  color?: string
+}
+
+export function ProgressRing({
+  progress,
+  size = 80,
+  strokeWidth = 6,
+  label,
+  value,
+  color = '#a78bfa'
+}: ProgressRingProps) {
+  const radius = (size - strokeWidth) / 2
+  const circumference = radius * 2 * Math.PI
+  const offset = circumference - (progress / 100) * circumference
+
+  return (
+    <div className="flex flex-col items-center">
+      <div className="relative" style={{ width: size, height: size }}>
+        <svg className="transform -rotate-90" width={size} height={size}>
+          <circle
+            cx={size / 2} cy={size / 2} r={radius}
+            fill="none" stroke="rgba(255, 255, 255, 0.1)" strokeWidth={strokeWidth}
+          />
+          <circle
+            cx={size / 2} cy={size / 2} r={radius}
+            fill="none" stroke={color} strokeWidth={strokeWidth}
+            strokeDasharray={circumference} strokeDashoffset={offset}
+            strokeLinecap="round"
+            style={{ transition: 'stroke-dashoffset 0.5s ease' }}
+          />
+        </svg>
+        <div className="absolute inset-0 flex items-center justify-center">
+          <span className="text-lg font-bold text-white">{value}</span>
+        </div>
+      </div>
+      <span className="mt-2 text-xs text-white/50">{label}</span>
+    </div>
+  )
+}