Strut windows committed zero height to layer-shell during
early init, causing a protocol error and session exit. Wrap
height and exclusionZone in Math.max(1, ...) for top bar
and dock.
Persisted gamingModeEnabled=true with hardcoded
gameCenterOpen=false hid panels with no overlay visible.
Initialize gameCenterOpen from the stored setting.
Fix HUD visibility regression from an emergency visible:true
override. Various null-guard and positioning fixes from
static analysis across the gaming shell QML.
