[Feature]: Improve scrolling and button remapping parity for MX Master 3

### Pre-flight checklist

- [x] I searched existing issues and the [Roadmap](https://github.com/AprilNEA/OpenLogi#roadmap), and this isn't already tracked.

### Problem / motivation

I just came to this tool from the official Logi+ and here are 3 massive throw backs of this software:

1. The scrolling experience is not so fluent and smooth
2. It´s not possible to set the zoom option for the thumb wheel (I am using MX3 Master) - this is very useful in many applications like Photoshop or Word etc.
3. The DPI toggle - I used it as a Back button and it worked almost everywhere. No I set it as back button for browser and it doesn't work

### Proposed solution

No idea

### Alternatives considered

_No response_

### Related area(s)

- [ ] GUI
- [ ] CLI
- [x] Button actions / remapping
- [ ] DPI
- [ ] SmartShift
- [ ] Per-application profiles
- [x] Configuration (TOML)
- [ ] Auto-update
- [ ] Other

### Additional context

_No response_

Start by examining the button actions/remapping and configuration (TOML) areas related to the MX Master 3. The issue requests smoother scrolling, thumb-wheel zoom mapping, and DPI-as-Back behavior, but gives no files, tests, implementation approach, or acceptance criteria; define those boundaries before judging the work complete.

Written by the indexing model from the issue text.