test: preview regression results in CI

[Hoblovski]

What type of PR is this?

test: 修复回归测试的输出，能在 github action 预览回归测试的具体错误啥样。
以前加的，没改业务代码。

原因：现在我们只知道有没有 break 东西，不知道具体 break 了啥（除非手动下载结果比较）。
我们相信，能方便地看到 pr 具体 break 了哪些东西以后，pr 会更可靠。

例子：https://github.com/Hoblovski/abcoder/actions/runs/19861553755/job/56912738322

Check the PR title.

• This PR title match the format: <type>(optional scope): <description>
• The description of this PR title is user-oriented and clear enough for others to understand.
• Attach the PR updating the user documentation if the current PR requires user awareness at the usage level. User docs repo

(Optional) Translate the PR title into Chinese.

(Optional) More detailed description for this PR(en: English/zh: Chinese).

en:
zh(optional):

(Optional) Which issue(s) this PR fixes:

(optional) The PR that updates user documentation:

[Hoblovski]

另一个例子： @Duslia 的新 PR 的改动 https://github.com/Hoblovski/abcoder/actions/runs/20573280609/job/59084744454?pr=7