Zip format releases

Hello! Thank y'all for maintaining these tools, they've been a blessing for building our game's asset pipeline.

One problem I've run into is that we want to automatically install and manage the version of the KTX tools on developer machines. There are some great tools to manage this within repositories, like [mise-en-place](https://mise.jdx.dev/), but these tools expect tar.gz or zip files, generally.

Releases for Windows and macOS are only available as installers (exe and pkg) which generally aren't supported by tools like mise and are harder to automate in CI pipelines. However, the Linux and iOS builds are already available as tar.bz2 and zip formats.

Would it be possible to add a ZIP packaged version of the KTX tools for Windows and macOS? If so, would y'all accept a contribution adding that to the release matrix?

Thank you!

Start by locating the release packaging matrix for the KTX tools and reviewing how the existing Windows, macOS, Linux, and iOS artifacts are produced. Determine the changes needed to produce ZIP packages for Windows and macOS, then verify that both archives are included in the release outputs alongside the existing installers.

Written by the indexing model from the issue text.