Add fail-closed Belgian training loop

scripts/render_operator_yolo_label_qa_contact_sheets.py

@@ -212,6 +212,8 @@ def draw_tile_card(
         top = max(header_height, y_center - height / 2)
         right = min(thumb_size - 1, x_center + width / 2)
         bottom = min(thumb_size + header_height - 1, y_center + height / 2)
+        if right < left or bottom < top:
+            continue
         draw.rectangle((left, top, right, bottom), outline=(255, 214, 10), width=3)
 
     return card
@@ -370,7 +372,7 @@ def write_markdown(report: dict[str, Any], output_dir: Path) -> None:
     if report["contact_sheets"]:
         for sheet in report["contact_sheets"]:
             lines.append(f"- `{sheet['path']}` ({sheet['tile_count']} tiles)")
-            lines.append(f"")
+            lines.append("")
             lines.append(f"![{sheet['path']}]({sheet['path']})")
             lines.append("")
     else: