- Driver now drains SYN/repeat/unknown events in a loop instead of
returning None on the first non-key event
- Snake drains all pending input events per tick, applies only the
latest direction change (prevents stale event accumulation)
- Add VirtIO input device driver (device ID 18) reading from eventq
- Translate Linux keycodes (WASD, arrows) to InputEvent
- Kernel probes for VirtIO input device, falls back to UART
- Add -device virtio-keyboard-device to run-gui Makefile target
- input-qemu tries VirtIO first, falls back to UART
