Type Alias PostVmCallback 

pub type PostVmCallback = fn(&VmResult) -> Result<()>;

Shared callback signature for the KtstrTestEntry::post_vm and KtstrTestEntry::post_vm_unconditional host-side hooks. Both fields wrap this same shape in Option<_>; the alias collapses the open-coded fn(&crate::vmm::VmResult) -> anyhow::Result<()> repetition at the field declarations and at the matching with_post_vm{,_unconditional} builder parameters. Future post-VM hooks (e.g. an expect_auto_repro artifact-existence checker) plug into the same shape without triplicating the signature.