fix: Overlay-Zellen ohne _heal_row_gaps positionieren (skip_heal_gaps)

_heal_row_gaps verschiebt Zell-Positionen nach Entfernung von Artefakt-Zeilen,
was im Overlay zu sichtbarem Versatz fuehrt (z.B. 23px bei "badge").
Neuer skip_heal_gaps Parameter in build_cell_grid_v2 und words-Endpoint
behaelt die exakten Zeilen-Positionen bei.

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

klausur-service/backend/cv_cell_grid.py

@@ -264,6 +264,7 @@ def build_cell_grid_v2(
     lang: str = "eng+deu",
     ocr_engine: str = "auto",
     img_bgr: Optional[np.ndarray] = None,
+    skip_heal_gaps: bool = False,
 ) -> Tuple[List[Dict[str, Any]], List[Dict[str, Any]]]:
     """Hybrid Grid: full-page OCR for broad columns, cell-crop for narrow ones.
 
@@ -330,7 +331,12 @@ def build_cell_grid_v2(
     else:
         bottom_bound = content_rows[-1].y + content_rows[-1].height
 
-    _heal_row_gaps(content_rows, top_bound=top_bound, bottom_bound=bottom_bound)
+    # skip_heal_gaps: When True, keep cell positions at their exact row geometry
+    # positions without expanding to fill gaps from removed rows.  Useful for
+    # overlay rendering where pixel-precise positioning matters more than
+    # full-coverage OCR crops.
+    if not skip_heal_gaps:
+        _heal_row_gaps(content_rows, top_bound=top_bound, bottom_bound=bottom_bound)
 
     relevant_cols.sort(key=lambda c: c.x)