fix(release): extract only Windows guest payload

[ZhiXiao-Lin]

Summary

• extract only a3s-box-guest-init from the Linux archive during Windows packaging
• avoid asking Windows tar to create unrelated Unix libkrun symlinks

Root cause

The final v3.1.0 run built every Windows binary successfully, then failed while extracting the complete Linux archive. Windows tar could not materialize the Linux libkrun*.so symlink chain. The Windows package only consumes the Linux guest executable.

Validation

• downloaded the exact linux-x86_64 artifact from release run 30016929743
• selectively extracted the exact guest member
• verified the extracted member is a regular file and no symlinks were created
• release YAML parses and the Windows package Bash block passes bash -n