Feature: Add option to launch detached VM

[d3bvstack]

Problem

Currently, running a VM with vmctl requires keeping the terminal open for the duration of the VM session. This is inconvenient for users who want to start a VM and continue using the terminal for other tasks.

Proposed Solution

Add an option to vmctl to allow launching a VM in detached mode so that the VM continues running even after the terminal session ends. This could be implemented as a --detached flag or similar.

Acceptance Criteria

• Users can run a VM in detached mode without needing the terminal to stay open.
• Proper documentation is added for the new option.
• Detached VMs can be managed (listed, stopped, etc.) via vmctl commands.

Additional context

This enhances usability, particularly for long-running workloads or server VMs.