Replace crosvm xhci-based USB passthrough with usbip-rs over vsock,
enabling USB passthrough for both crosvm and cloud-hypervisor VMs.
Guest runs a persistent usbip-rs client listener on vsock port 5002.
Host runs one sandboxed usbip-rs host connect process per attached
device as a systemd template service (vmsilo-<vm>-usb@<devpath>).
Eliminates the JSON state file, file locking, and crosvm-specific
shell helper library in favor of systemd as the source of truth.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Davíð Steinn Geirsson
08709827fb