[Bug]: 使用ProcessParallelEdges，在没有双向边时，会把我edge的type改成line

### Describe the bug / 问题描述

使用ProcessParallelEdges，在没有双向边时，会把我edge的type改成line,可以在工具定义的时候设置默认type吗，或者给个回调函数

### Reproduction link / 复现链接

https://stackblitz.com/edit/vitejs-vite-o2hsa1zy?file=src%2Fmain.js

### Steps to Reproduce the Bug or Issue / 重现步骤

_No response_

### Version / 版本

🆕 5.x

### OS / 操作系统

- [ ] macOS
- [x] Windows
- [ ] Linux
- [ ] Others / 其他

### Browser / 浏览器

- [x] Chrome
- [ ] Edge
- [ ] Firefox
- [ ] Safari (Limited support / 有限支持)
- [ ] IE (Nonsupport / 不支持)
- [ ] Others / 其他

Start with the ProcessParallelEdges implementation and reproduce the behavior using the linked StackBlitz example. Check what happens to an edge's type when no bidirectional edge exists; done means the reported type is preserved or the requested default-type or callback behavior is clearly addressed and covered by a regression test.

Written by the indexing model from the issue text.