feat: add Kombi-Vergleich mode for side-by-side Paddle vs RapidOCR comparison

Add /rapid-kombi backend endpoint using local RapidOCR + Tesseract merge,
KombiCompareStep component for parallel execution and side-by-side overlay,
and wordResultOverride prop on OverlayReconstruction for direct data injection.

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

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

@@ -11,12 +11,13 @@ import { StepRowDetection } from '@/components/ocr-pipeline/StepRowDetection'
 import { StepWordRecognition } from '@/components/ocr-pipeline/StepWordRecognition'
 import { OverlayReconstruction } from '@/components/ocr-overlay/OverlayReconstruction'
 import { PaddleDirectStep } from '@/components/ocr-overlay/PaddleDirectStep'
-import { OVERLAY_PIPELINE_STEPS, PADDLE_DIRECT_STEPS, KOMBI_STEPS, DOCUMENT_CATEGORIES, dbStepToOverlayUi, type PipelineStep, type SessionListItem, type DocumentCategory } from './types'
+import { KombiCompareStep } from '@/components/ocr-overlay/KombiCompareStep'
+import { OVERLAY_PIPELINE_STEPS, PADDLE_DIRECT_STEPS, KOMBI_STEPS, KOMBI_COMPARE_STEPS, DOCUMENT_CATEGORIES, dbStepToOverlayUi, type PipelineStep, type SessionListItem, type DocumentCategory } from './types'
 
 const KLAUSUR_API = '/klausur-api'
 
 export default function OcrOverlayPage() {
-  const [mode, setMode] = useState<'pipeline' | 'paddle-direct' | 'kombi'>('pipeline')
+  const [mode, setMode] = useState<'pipeline' | 'paddle-direct' | 'kombi' | 'kombi-compare'>('pipeline')
   const [currentStep, setCurrentStep] = useState(0)
   const [sessionId, setSessionId] = useState<string | null>(null)
   const [sessionName, setSessionName] = useState<string>('')
@@ -63,14 +64,15 @@ export default function OcrOverlayPage() {
       setSessionName(data.name || data.filename || '')
       setActiveCategory(data.document_category || undefined)
 
-      // Check if this session was processed with paddle_direct or kombi
+      // Check if this session was processed with paddle_direct, kombi, or rapid_kombi
       const ocrEngine = data.word_result?.ocr_engine
       const isPaddleDirect = ocrEngine === 'paddle_direct'
       const isKombi = ocrEngine === 'kombi'
+      const isRapidKombi = ocrEngine === 'rapid_kombi'
 
-      if (isPaddleDirect || isKombi) {
-        const m = isKombi ? 'kombi' : 'paddle-direct'
-        const baseSteps = isKombi ? KOMBI_STEPS : PADDLE_DIRECT_STEPS
+      if (isPaddleDirect || isKombi || isRapidKombi) {
+        const m = isKombi ? 'kombi' : isPaddleDirect ? 'paddle-direct' : 'kombi-compare'
+        const baseSteps = isKombi ? KOMBI_STEPS : isRapidKombi ? KOMBI_COMPARE_STEPS : PADDLE_DIRECT_STEPS
         setMode(m)
         setSteps(
           baseSteps.map((s, i) => ({
@@ -105,7 +107,7 @@ export default function OcrOverlayPage() {
       if (sessionId === sid) {
         setSessionId(null)
         setCurrentStep(0)
-        const baseSteps = mode === 'kombi' ? KOMBI_STEPS : mode === 'paddle-direct' ? PADDLE_DIRECT_STEPS : OVERLAY_PIPELINE_STEPS
+        const baseSteps = mode === 'kombi' ? KOMBI_STEPS : mode === 'kombi-compare' ? KOMBI_COMPARE_STEPS : mode === 'paddle-direct' ? PADDLE_DIRECT_STEPS : OVERLAY_PIPELINE_STEPS
         setSteps(baseSteps.map((s, i) => ({ ...s, status: i === 0 ? 'active' : 'pending' })))
       }
     } catch (e) {
@@ -162,7 +164,7 @@ export default function OcrOverlayPage() {
   const handleNext = () => {
     if (currentStep >= steps.length - 1) {
       // Last step completed — return to session list
-      const baseSteps = mode === 'kombi' ? KOMBI_STEPS : mode === 'paddle-direct' ? PADDLE_DIRECT_STEPS : OVERLAY_PIPELINE_STEPS
+      const baseSteps = mode === 'kombi' ? KOMBI_STEPS : mode === 'kombi-compare' ? KOMBI_COMPARE_STEPS : mode === 'paddle-direct' ? PADDLE_DIRECT_STEPS : OVERLAY_PIPELINE_STEPS
       setSteps(baseSteps.map((s, i) => ({ ...s, status: i === 0 ? 'active' : 'pending' })))
       setCurrentStep(0)
       setSessionId(null)
@@ -191,7 +193,7 @@ export default function OcrOverlayPage() {
     setSessionId(null)
     setSessionName('')
     setCurrentStep(0)
-    const baseSteps = mode === 'kombi' ? KOMBI_STEPS : mode === 'paddle-direct' ? PADDLE_DIRECT_STEPS : OVERLAY_PIPELINE_STEPS
+    const baseSteps = mode === 'kombi' ? KOMBI_STEPS : mode === 'kombi-compare' ? KOMBI_COMPARE_STEPS : mode === 'paddle-direct' ? PADDLE_DIRECT_STEPS : OVERLAY_PIPELINE_STEPS
     setSteps(baseSteps.map((s, i) => ({ ...s, status: i === 0 ? 'active' : 'pending' })))
   }
 
@@ -230,7 +232,7 @@ export default function OcrOverlayPage() {
   }, [sessionId, goToStep])
 
   const renderStep = () => {
-    if (mode === 'paddle-direct' || mode === 'kombi') {
+    if (mode === 'paddle-direct' || mode === 'kombi' || mode === 'kombi-compare') {
       switch (currentStep) {
         case 0:
           return <StepOrientation sessionId={sessionId} onNext={handleOrientationComplete} />
@@ -241,6 +243,9 @@ export default function OcrOverlayPage() {
         case 3:
           return <StepCrop sessionId={sessionId} onNext={handleNext} />
         case 4:
+          if (mode === 'kombi-compare') {
+            return <KombiCompareStep sessionId={sessionId} onNext={handleNext} />
+          }
           return mode === 'kombi' ? (
             <PaddleDirectStep
               sessionId={sessionId}
@@ -514,6 +519,22 @@ export default function OcrOverlayPage() {
         >
           Kombi (5 Schritte)
         </button>
+        <button
+          onClick={() => {
+            if (mode === 'kombi-compare') return
+            setMode('kombi-compare')
+            setCurrentStep(0)
+            setSessionId(null)
+            setSteps(KOMBI_COMPARE_STEPS.map((s, i) => ({ ...s, status: i === 0 ? 'active' : 'pending' })))
+          }}
+          className={`px-3 py-1.5 text-xs font-medium rounded-md transition-colors ${
+            mode === 'kombi-compare'
+              ? 'bg-white dark:bg-gray-700 text-gray-700 dark:text-gray-200 shadow-sm'
+              : 'text-gray-500 dark:text-gray-400 hover:text-gray-700 dark:hover:text-gray-300'
+          }`}
+        >
+          Vergleich (5 Schritte)
+        </button>
       </div>
 
       <PipelineStepper

admin-lehrer/app/(admin)/ai/ocr-overlay/types.ts

@@ -72,6 +72,18 @@ export const KOMBI_STEPS: PipelineStep[] = [
   { id: 'kombi', name: 'Paddle + Tesseract', icon: '🔀', status: 'pending' },
 ]
 
+/**
+ * 5-step pipeline for Kombi-Vergleich mode (Paddle-Kombi vs Rapid-Kombi side-by-side).
+ * Same preprocessing, then both kombi engines run in parallel and are shown side-by-side.
+ */
+export const KOMBI_COMPARE_STEPS: PipelineStep[] = [
+  { id: 'orientation', name: 'Orientierung', icon: '🔄', status: 'pending' },
+  { id: 'deskew', name: 'Begradigung', icon: '📐', status: 'pending' },
+  { id: 'dewarp', name: 'Entzerrung', icon: '🔧', status: 'pending' },
+  { id: 'crop', name: 'Zuschneiden', icon: '✂️', status: 'pending' },
+  { id: 'kombi-compare', name: 'Kombi-Vergleich', icon: '⚖️', status: 'pending' },
+]
+
 /** Map from DB step to overlay UI step index */
 export function dbStepToOverlayUi(dbStep: number): number {
   // DB: 1=start, 2=orient, 3=deskew, 4=dewarp, 5=crop, 6=columns, 7=rows, 8=words, 9=recon, 10=gt