fix: PaddleOCR engine forces words_first in frontend to match backend

When engine=paddle is selected, the backend overrides grid_method to
words_first and returns plain JSON (no SSE streaming). The frontend
was not aware of this override — it sent stream=true and tried to parse
SSE events from a JSON response, resulting in "Keine Daten".

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

admin-lehrer/components/ocr-pipeline/StepWordRecognition.tsx

@@ -108,12 +108,16 @@ export function StepWordRecognition({ sessionId, onNext, goToStep, skipHealGaps
     setGridResult(null)
 
     try {
+      // PaddleOCR forces words_first on the backend, so align frontend accordingly
+      const effectiveGridMethod = eng === 'paddle' ? 'words_first' : gridMethod
+      const useStream = effectiveGridMethod === 'v2'
+
       // Retry once if initial request fails (e.g. after container restart,
       // session cache may not be warm yet when navigating via wizard)
       let res: Response | null = null
       for (let attempt = 0; attempt < 2; attempt++) {
         res = await fetch(
-          `${KLAUSUR_API}/api/v1/ocr-pipeline/sessions/${sessionId}/words?stream=${gridMethod === 'v2' ? 'true' : 'false'}&engine=${eng}&pronunciation=${pronunciation}${skipHealGaps ? '&skip_heal_gaps=true' : ''}&grid_method=${gridMethod}`,
+          `${KLAUSUR_API}/api/v1/ocr-pipeline/sessions/${sessionId}/words?stream=${useStream ? 'true' : 'false'}&engine=${eng}&pronunciation=${pronunciation}${skipHealGaps ? '&skip_heal_gaps=true' : ''}&grid_method=${effectiveGridMethod}`,
           { method: 'POST' },
         )
         if (res.ok) break
@@ -129,8 +133,8 @@ export function StepWordRecognition({ sessionId, onNext, goToStep, skipHealGaps
         throw new Error(err.detail || 'Worterkennung fehlgeschlagen')
       }
 
-      // words_first returns plain JSON (no streaming)
-      if (gridMethod === 'words_first') {
+      // words_first / paddle returns plain JSON (no streaming)
+      if (!useStream) {
         const data = await res.json() as GridResult
         applyGridResult(data)
         return