- Added persistent '+ Add Item' button at bottom of each storage location
- Button is centered and always visible (whether location has 0 or many items)
- Removed redundant '+ Add' button from storage location header (kept trash button)
- Reverted empty state to simple message instead of special button
- Added CSS for .rpg-storage-add-item-container to center button with margin
- Matches UI pattern from On Person and Assets tabs
- Removed debug logging from inventoryActions.js