Feature Request: Custom Installation Directory and VM Export/Import Functionality

Hello! First of all, thank you for this incredible project. It's a game-changer for GPU-PV and nested virtualization workloads without the hassle of Hyper-V Manager.
Currently, the VMs are stored in default system paths (like C:\ProgramData\AppSandbox or %LocalAppData%). These .vhdx files can quickly grow to dozens of gigabytes. For users with limited C: drive SSD space, or those who want to keep their VMs on a secondary drive, this becomes an issue.
Additionally, while the Snapshot feature is fantastic for state rollbacks, there is currently no straightforward way to migrate a "golden" VM to another physical device, or back it up safely before an OS format.
Proposed Solutions:

1. Custom Storage Path: Add an option in the GUI/CLI to select the default installation/storage directory for new VMs (e.g., D:\AppSandbox_VMs).
2. Export/Import Feature: Introduce an official way to export a VM (bundling the .vhdx and .json configs) and import it back on a fresh install or a different machine.
   Thanks for your hard work on this!

Start by locating the GUI/CLI code that chooses default VM storage paths and manages the .vhdx and .json files. Trace how new VMs are created and restored; done should include configurable storage for new VMs plus a reliable export/import flow that works on another machine or fresh installation.