Port of gmToolbarUI::PostInit (slot wiring) + UpdateFromPlayerDesc (flush-and-bind
shortcuts from PlayerDescription) + SetDelayedShortcutNum (deferred ItemAdded rebind)
+ UseShortcut (click → useItem callback).
UiItemSlot gains Clicked (Action?) + OnEvent override (MouseDown → Clicked?.Invoke())
matching the retail UIElement_UIItem click dispatch pattern. UiEvent is a positional
record struct so the OnEvent override reads e.Type (int) against UiEventType.MouseDown
(const int 0x201) — confirmed from UiEvent.cs + UiText.cs before writing.
Three tests green (populate bound slot, deferred rebind on ItemAdded, click fires useItem).
Full suite: 0 failures.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>