refactor: rename PaddleOCR → PP-OCRv5 in frontend, remove Kombi-Vergleich tab

Since ocr_region_paddle() now runs RapidOCR locally (same PP-OCRv5 models),
the "PaddleOCR (Hetzner)" labels were misleading. Renamed to "PP-OCRv5 (lokal)".
Removed the Kombi-Vergleich tab since both sides would produce identical results.

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

admin-lehrer/components/ocr-overlay/PaddleDirectStep.tsx

@@ -30,11 +30,11 @@ export function PaddleDirectStep({
   sessionId,
   onNext,
   endpoint = 'paddle-direct',
-  title = 'Paddle Direct',
-  description = 'PaddleOCR erkennt alle Woerter direkt auf dem Originalbild — ohne Begradigung, Entzerrung oder Zuschnitt.',
+  title = 'PP-OCRv5 Direct',
+  description = 'PP-OCRv5 (lokal via RapidOCR) erkennt alle Woerter direkt auf dem Originalbild — ohne Begradigung, Entzerrung oder Zuschnitt.',
   icon = '⚡',
-  buttonLabel = 'PaddleOCR starten',
-  runningLabel = 'PaddleOCR laeuft...',
+  buttonLabel = 'PP-OCRv5 starten',
+  runningLabel = 'PP-OCRv5 laeuft...',
   engineKey = 'paddle_direct',
 }: PaddleDirectStepProps) {
   const [phase, setPhase] = useState<Phase>('idle')