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/components/ocr-overlay/OverlayReconstruction.tsx

@@ -10,6 +10,8 @@ const KLAUSUR_API = '/klausur-api'
 interface OverlayReconstructionProps {
   sessionId: string | null
   onNext: () => void
+  /** When set, use this data directly instead of fetching from the session API. */
+  wordResultOverride?: { cells: GridCell[]; image_width: number; image_height: number; [key: string]: unknown }
 }
 
 interface EditableCell {
@@ -24,7 +26,7 @@ interface EditableCell {
 
 type UndoAction = { cellId: string; oldText: string; newText: string }
 
-export function OverlayReconstruction({ sessionId, onNext }: OverlayReconstructionProps) {
+export function OverlayReconstruction({ sessionId, onNext, wordResultOverride }: OverlayReconstructionProps) {
   const [status, setStatus] = useState<'loading' | 'ready' | 'saving' | 'saved' | 'error'>('loading')
   const [error, setError] = useState('')
   const [cells, setCells] = useState<EditableCell[]>([])
@@ -78,10 +80,39 @@ export function OverlayReconstruction({ sessionId, onNext }: OverlayReconstructi
 
   // Load session data
   useEffect(() => {
+    if (wordResultOverride) {
+      applyWordResult(wordResultOverride)
+      return
+    }
     if (!sessionId) return
     loadSessionData()
   // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [sessionId])
+  }, [sessionId, wordResultOverride])
+
+  const applyWordResult = (wordResult: { cells: GridCell[]; image_width: number; image_height: number; [key: string]: unknown }) => {
+    const rawGridCells: GridCell[] = wordResult.cells || []
+    setGridCells(rawGridCells)
+
+    const editableCells: EditableCell[] = rawGridCells.map(c => ({
+      cellId: c.cell_id,
+      text: c.text,
+      originalText: c.text,
+      bboxPct: c.bbox_pct,
+      colType: c.col_type,
+      rowIndex: c.row_index,
+      colIndex: c.col_index,
+    }))
+    setCells(editableCells)
+    setEditedTexts(new Map())
+    setUndoStack([])
+    setRedoStack([])
+
+    if (wordResult.image_width && wordResult.image_height) {
+      setImageNaturalSize({ w: wordResult.image_width, h: wordResult.image_height })
+    }
+
+    setStatus('ready')
+  }
 
   const loadSessionData = async () => {
     if (!sessionId) return
@@ -98,33 +129,11 @@ export function OverlayReconstruction({ sessionId, onNext }: OverlayReconstructi
         return
       }
 
-      const rawGridCells: GridCell[] = wordResult.cells || []
-      setGridCells(rawGridCells)
-
-      const editableCells: EditableCell[] = rawGridCells.map(c => ({
-        cellId: c.cell_id,
-        text: c.text,
-        originalText: c.text,
-        bboxPct: c.bbox_pct,
-        colType: c.col_type,
-        rowIndex: c.row_index,
-        colIndex: c.col_index,
-      }))
-      setCells(editableCells)
-      setEditedTexts(new Map())
-      setUndoStack([])
-      setRedoStack([])
+      applyWordResult(wordResult as unknown as { cells: GridCell[]; image_width: number; image_height: number })
 
       // Load rows
       const rowResult: RowResult | undefined = data.row_result
       if (rowResult?.rows) setRows(rowResult.rows)
-
-      // Store image dimensions
-      if (wordResult.image_width && wordResult.image_height) {
-        setImageNaturalSize({ w: wordResult.image_width, h: wordResult.image_height })
-      }
-
-      setStatus('ready')
     } catch (e: unknown) {
       setError(e instanceof Error ? e.message : String(e))
       setStatus('error')