Implemented
- Desktop window and persistent multi-page frontend.
- Host diagnostics and local data paths.
- QEMU and qemu-img discovery with version probing.
- Linux KVM verification through /dev/kvm.
- VM definitions with validated resources.
- Thin-provisioned QCOW2 disk creation.
- QEMU start and stop with QMP control.
- Loopback noVNC guest console.
- Schema-v2 local configuration with atomic writes.