feat(boxing): update detail page quantity display and paichan_no style

- Change quantity display from "数量：N" to "N/total" format (boxed/total)
- Enlarge paichan_no font to 18px bold and right-align

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

lib/pages/boxing_detail_page.dart

@@ -22,9 +22,10 @@ class BoxingDetailPage extends StatelessWidget {
             Expanded(
               child: Text(
                 paichanNo,
+                textAlign: TextAlign.end,
                 style: const TextStyle(
-                  fontSize: 14,
-                  fontWeight: FontWeight.normal,
+                  fontSize: 18,
+                  fontWeight: FontWeight.bold,
                 ),
                 overflow: TextOverflow.ellipsis,
               ),
@@ -102,7 +103,7 @@ class BoxingDetailPage extends StatelessWidget {
                       ),
                       const SizedBox(width: 8),
                       Text(
-                        '数量：${item.quantity}',
+                        '${item.quantity}/${item.totalQuantity ?? '--'}',
                         style: const TextStyle(fontSize: 14),
                       ),
                     ],