Two gaps in the owner-change handling, both found on device.
The push at adopt time can lose a race. osk-switch sleeps 0.3s before
its deliberate SetVisible(true), and stevia self-shows once it has
finished coming up - both land after the shell has spoken. Measured:
adopt+hide 07:37:51, Visible=true 07:37:52, leaving oskOpen=false with a
keyboard on the screen. Re-assert when the settle window closes so the
last speaker is not the winner.
And the oskSwap gesture never recorded that a swap means the user wants
a keyboard, so osk-switch's re-show and the shell's stale false were
racing with nothing to arbitrate them. Declare the intent first.