fix: crash and build

[KorigamiK]

This fixes linux builds with qt 6.8.
Fixes crash when calling SetWindowRectCommand with bad input

[ahrm]

1. Can you squash these commits, there are some commits that are undoing each other's work, they needlessly pollute the history.
2. No need to do an ifdef for the header, just use #include <QThread> if the other one doesn't work.

[KorigamiK]

You can squash the commits when merging on GitHub (click the drop-down next to the merge button)

I couldn't figure out why the ci is failing so I added that ifdef, is it not because of that?

[ahrm]

No, the reason for the build failure was a mistake on my part, I should have included either qthread.h or QThread but instead I included qthread, it did not trigger an error for me on windows because paths are case-insensitive on windows.