Zod 4 support

Hi!

I really need Zod 4 support for my project with Vee-Validate. However Vee-Validate 5-beta.1 is currently broken for me, a lot of things are not working (and it makes sense since it is a beta).

For my project I cannot even rely on beta dependencies, so even if v5 takes more work, could we bring a few patches to support Zod 4 with VV 4?

Everything more or less works already, I'm just having issues with union errors for instance in my case. And I feel like we should keep this opened until v5 is stable at least