Fix cyclic TSharedPtr references causing memory leaks in item UI widgets

[Copilot]

Slate widget trees had multiple cyclic TSharedPtr reference patterns preventing ref counts from ever reaching zero — widgets were never freed.

Cycles fixed

• SNaItemSlot ↔ BoxSlot: Parent holds TSharedPtr<SNaBoxSlot>, child delegates held TSharedPtr back to parent via BindSP
• SNaInventoryWrappedBox / SNaInventoryCanvas self-ref: BindEventsToUMG() called OnSlotXxx.AddSP(this, ...) on own member delegates — permanent self-reference
• SNaInventoryCanvas ↔ child slots: Canvas owns slots via TSharedPtr, child BoxSlot delegates held TSharedPtr back to canvas via CreateSP

All resolved by switching to BindRaw/CreateRaw — safe because child widgets cannot outlive their parent in the Slate tree:

// Before: creates strong back-reference → cycle
BoxSlot->OnPointed.BindSP(this, &SNaItemSlot::SlotPointedToList);

// After: raw pointer, no ref count increment
BoxSlot->OnPointed.BindRaw(this, &SNaItemSlot::SlotPointedToList);

Additional fixes

• UNaItemSlotList::List: TSharedRef → TSharedPtr (TSharedRef has no default ctor / Reset())
• UMGRef: Raw UObject* → TWeakObjectPtr in both SNaInventoryWrappedBox and SNaInventoryCanvas, with validity checks in all SlotXxxToUMG() forwarders
• SNaInventoryWrappedBox::Construct: UMGRef was never assigned from InArgs._FromUMG — BindEventsToUMG() was always a no-op
• SLATE_ATTRIBUTE type mismatches: Fixed broken types from recent rename (TSharedRef<FNaItemSlotStyle> → FNaItemSlotStyle*, wrong Container type, invalid TWeakObjectPtr<UNaItemSlotList*> syntax)
• SNaItemSlot::StylePtr: TSharedPtr<FNaItemSlotStyle> → raw pointer (style is stack-owned by UMG widget, TSharedPtr would double-free)
• SNaItemSlot::ItemSlotList: TWeakPtr → raw pointer (child→parent back-ref; TWeakPtr can't be assigned from raw ptr, broke compilation)

---

🔒 GitHub Advanced Security automatically protects Copilot coding agent pull requests. You can protect all pull requests by enabling Advanced Security for your repositories. Learn more about Advanced Security.