feat(pointer): virtio tablet as 2nd input dev (driver per-instance VAs, abs/btn decode), input server serves 2 devices on one notif; display software cursor, bar click switches window, presses/releases to front window in its px; k-ui hit-tests (press focuses, release on same presses, field only focuses)

scripts/test-qemu.sh

@@ -33,7 +33,7 @@ boot() {
         -kernel "${KERNEL}" \
         -drive "file=${IMAGE},if=none,format=raw,id=hd0" -device virtio-blk-device,drive=hd0 \
         -drive "file=${KEYS},if=none,format=raw,id=ks" -device virtio-blk-device,drive=ks \
-        -device virtio-rng-device -device virtio-gpu-device -device virtio-keyboard-device \
+        -device virtio-rng-device -device virtio-gpu-device -device virtio-keyboard-device -device virtio-tablet-device \
         -display none -serial "file:${LOG}" -monitor "unix:${MON},server,nowait"
     local s=$?
     wait