feat(ocr-pipeline): add Step 4 row detection UI in admin frontend

Insert rows step between columns and words in the pipeline wizard.
Shows overlay image, row list with type badges, and ground truth controls.

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

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

@@ -6,6 +6,7 @@ import { PipelineStepper } from '@/components/ocr-pipeline/PipelineStepper'
 import { StepDeskew } from '@/components/ocr-pipeline/StepDeskew'
 import { StepDewarp } from '@/components/ocr-pipeline/StepDewarp'
 import { StepColumnDetection } from '@/components/ocr-pipeline/StepColumnDetection'
+import { StepRowDetection } from '@/components/ocr-pipeline/StepRowDetection'
 import { StepWordRecognition } from '@/components/ocr-pipeline/StepWordRecognition'
 import { StepCoordinates } from '@/components/ocr-pipeline/StepCoordinates'
 import { StepReconstruction } from '@/components/ocr-pipeline/StepReconstruction'
@@ -142,10 +143,11 @@ export default function OcrPipelinePage() {
     1: 'Begradigung',
     2: 'Entzerrung',
     3: 'Spalten',
-    4: 'Woerter',
-    5: 'Koordinaten',
-    6: 'Rekonstruktion',
-    7: 'Validierung',
+    4: 'Zeilen',
+    5: 'Woerter',
+    6: 'Koordinaten',
+    7: 'Rekonstruktion',
+    8: 'Validierung',
   }
 
   const renderStep = () => {
@@ -157,12 +159,14 @@ export default function OcrPipelinePage() {
       case 2:
         return <StepColumnDetection sessionId={sessionId} onNext={handleNext} />
       case 3:
-        return <StepWordRecognition />
+        return <StepRowDetection sessionId={sessionId} onNext={handleNext} />
       case 4:
-        return <StepCoordinates />
+        return <StepWordRecognition />
       case 5:
-        return <StepReconstruction />
+        return <StepCoordinates />
       case 6:
+        return <StepReconstruction />
+      case 7:
         return <StepGroundTruth />
       default:
         return null