`move_traffic_light` was framing the close / minimize / zoom NSButtons
at `titlebar_height - traffic_light_position.y - button_h`. Once the
window opts into `NSFullSizeContentViewWindowMask`, the content layout
rectangle covers the whole frame and `titlebar_height()` returns 0 —
collapsing the origin to a large negative Y. macOS still painted the
buttons through its own caching layer at the title bar's natural
position, but the buttons' hit-test rectangle followed the frame off
screen, so clicking close / minimize / zoom did nothing.
Anchor the math against the close button's actual superview frame
height (the themeFrame, which equals the window height in Y-up
coordinates) so the visual position and the hit area stay in lockstep
no matter what mask combination the window opens with. `titlebar_height`
stays available for callers that want the legacy non-full-size
interpretation, with `#[allow(dead_code)]` and a docstring pointing at
this fix.
ZacharyZhang-NY
736ff08e90