Virtual item stacking (similar to empty slot stacking)

[veechs]

What will your feature request solve?

When there are multiple slots filled with the same item, it can be visually cluttered and slightly difficult to tell at a glance how many you have.

Describe the solution you'd like

Similar to empty slot stacking, provide an option to stack slots that contain the same item.

Additional features to consider:

• Display both the total item count and the number of slots represented.
• Provide an option for minimum gathering threshold (don't create the virtual stack until X slots of the same item are found).
• Allow/denylist modes where only specific items (or all except the specific items) are stacked.

Describe alternatives you've considered

The Bagshui info tooltip can tell you how many of an item you have, but it doesn't make the inventory look cleaner.

Additional context

Requested here.