Have 2 separate actions for mouse wheel in dank bar

### Feature Description

Hi. First thanks for this project. It is awesome.
Mouse wheel action in the dank bar is nice.
An improvement would be to do sthg similar to android smartphone: eg
- when you use the wheel on the left side of the bar it moves over workspaces
- when you use the wheel on the right side of the bar it moves over columns

### Use Case

then you can change workspace and change window with no need for keyboard

### Compositor(s)

Niri

### If Other, please specify

_No response_

### Proposed Solution

_No response_

### Alternatives/Existing Solutions

_No response_

Start by locating the dank bar's existing mouse-wheel handling and how the Niri integration changes workspaces and columns. Confirm whether the bar can distinguish wheel events by left and right side, then verify that each side triggers the requested navigation without changing the other behavior.

Written by the indexing model from the issue text.