fix: 修复层级删除和模型信息显示数值问题

- 层级删除loading显示的层级编号现在从1开始，与层级统计页面保持一致
- 修复Creo模型查看器中零件数量显示，现在显示正确的文件数量

🤖 Generated with [Claude Code](https://claude.ai/code)

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

src/components/model/CreoModelViewer.vue

@@ -38,7 +38,7 @@
           <div class="stats-grid">
             <div class="stat-item">
               <label>零件数量:</label>
-              <span>{{ modelData.data?.partCount || 0 }}个</span>
+              <span>{{ Math.max(0, (modelData.data?.partCount || 0) - 1) }}个</span>
             </div>
             <div class="stat-item">
               <label>装配层级:</label>

src/services/creoApi.js

@@ -187,7 +187,7 @@ class CreoApiService {
     }, {
       operationContext: {
         software: 'Creo',
-        operation: `层级删除 - 层级${targetLevel}`
+        operation: `层级删除 - 层级${targetLevel + 1}`
       }
     })
   }