fix(ocr): use correct Kraken record attributes for line geometry

BaselineOCRRecord has 'baseline' and 'boundary' attributes, not 'line'
and 'cuts'. The fallback used record.line which doesn't exist, causing
AttributeError on every Kurrent OCR page.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ocr-service/engines/kraken.py

@@ -47,7 +47,7 @@ def extract_page_blocks(image, page_idx: int, language: str = "de") -> list[dict
     pred_it = rpred.rpred(_model, image, baseline_seg)
 
     for record in pred_it:
-        polygon_pts = record.cuts if hasattr(record, "cuts") else []
+        polygon_pts = record.boundary if hasattr(record, "boundary") and record.boundary else []
 
         if polygon_pts:
             xs = [p[0] for p in polygon_pts]
@@ -55,8 +55,8 @@ def extract_page_blocks(image, page_idx: int, language: str = "de") -> list[dict
             x1, y1 = min(xs), min(ys)
             x2, y2 = max(xs), max(ys)
         else:
-            xs = [p[0] for p in record.line]
-            ys = [p[1] for p in record.line]
+            xs = [p[0] for p in record.baseline]
+            ys = [p[1] for p in record.baseline]
             x1, y1 = min(xs), min(ys) - 5
             x2, y2 = max(xs), max(ys) + 5