- Godot 4's CallbackTweener doesn't have .bind() — move .bind() call
inside tween_callback() for 3 callback sites
- Shrink InventoryBackpack Control to 60x60 (offset_right -70) so click
area matches the visible BackpackIcon square
- ItemDefinition.gd: Resource class with id, name, combination_category
- ItemDefinition.gd.uid: UID cache file
- InventoryManager.gd.uid: UID cache file (script was committed, UID was not)
- inventory-prd.md: Original product requirements document (791 lines)
- docs/plans/2026-04-26-001-feat-inventory-backpack-system-plan.md:
Implementation plan with 6 units and 5 user-directed edits
