fix: _group_words_into_lines nach cv_ocr_engines.py verschieben

Funktion war nur in cv_review.py definiert, wurde aber auch in
cv_ocr_engines.py und cv_layout.py benutzt — NameError zur Laufzeit.

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

klausur-service/backend/cv_ocr_engines.py

@@ -37,6 +37,32 @@ except ImportError:
 # Pipeline Step 5: Word Grid from Columns × Rows
 # =============================================================================
 
+def _group_words_into_lines(words: List[Dict], y_tolerance_px: int = 20) -> List[List[Dict]]:
+    """Group words by Y position into lines, sorted by X within each line."""
+    if not words:
+        return []
+
+    sorted_words = sorted(words, key=lambda w: (w['top'], w['left']))
+    lines: List[List[Dict]] = []
+    current_line: List[Dict] = [sorted_words[0]]
+    current_y = sorted_words[0]['top']
+
+    for word in sorted_words[1:]:
+        if abs(word['top'] - current_y) <= y_tolerance_px:
+            current_line.append(word)
+        else:
+            current_line.sort(key=lambda w: w['left'])
+            lines.append(current_line)
+            current_line = [word]
+            current_y = word['top']
+
+    if current_line:
+        current_line.sort(key=lambda w: w['left'])
+        lines.append(current_line)
+
+    return lines
+
+
 def _words_to_reading_order_lines(words: List[Dict], y_tolerance_px: int = 15) -> List[str]:
     """Group OCR words into visual lines in reading order.