启动后出现僵尸进程

## 版本信息
```
Flatpak 1.14.6

Linux QQ com.qq.QQ 3.2.19_250904 stable
```
## 系统版本
```
Linux linux-desktop 6.11.0-25-generic #25~24.04.1-Ubuntu SMP PREEMPT_DYNAMIC Tue Apr 15 17:20:50 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
```

## pstree 信息
```
pstree 5084 -a
qq
├─qq
│ └─qq
│ └─16*[{qq}]
├─qq
│ └─6*[{qq}]
├─(zypak-sandbox)
└─83*[{qq}]

```
## 僵尸进程
```
ps -ef | grep defunct
xxx 5093 5084 0 09:46 ? 00:00:00 [zypak-sandbox]
```

Start by reproducing the startup state with pstree and checking for defunct processes with ps -ef | grep defunct, using the reported Flatpak, QQ, and Ubuntu versions. Done means identifying why zypak-sandbox becomes a zombie and documenting or validating a fix for that startup behavior.

Written by the indexing model from the issue text.