feat（新功能）: 修复结果图宽度异常问题

fix（修复bug）:
docs（文档变更）:
refactor（重构）:
test(增加测试):

app/service/design_fast/utils/synthesis_item.py

@@ -207,7 +207,7 @@ def update_base_size_priority(layers, size):
         if info['name'] == 'mannequin':
             new_height = info['image'].height
     max_x = max(x_list)
-    new_width = max_x - min_x
+    new_width = max_x - min_x * 2
     # 更新坐标
     for info in layers:
         info['adaptive_position'] = (info['position'][0], info['position'][1] - min_x)