Inventory System

Build EnhancedItem, the data template every sword and potion is stamped from, with an ItemType enum and a summary line.

Build InventorySlot, which holds one item plus a quantity and caps a stack at its max, handing back the overflow.

Spend from a slot and fold two matching stacks into one, reusing the cap-and-overflow logic you already wrote.

Build AdvancedInventory, a Node that owns an Array of slots and builds them empty when it enters the scene.

Write add_item so loot fills matching stacks first, then spills into empty slots, and reports what did not fit.

Total an item across stacks, check you hold enough, and spend an item that may be spread across several slots.

Give the bag a weight it recomputes on every change, and a gate that refuses items that would make it too heavy.

Add use_item so a potion fires its effect and drops one from the stack, keeping the bag reusable across projects.

Make items equippable and build EquipmentSystem, the rack that totals the power of everything you have on.

Wire the bag and rack into a live readout, then build the on-screen inventory in code: a slot grid, right-click to use, drag-and-drop between slots, and world pickup into the bag.