[Feature]: MX Master 3 no pointer wheel. The buttons below the pointer wheel cannot start the explore

### 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

There is no place for the problem feedback pointer wheel to configure the middle button below the wheel. Officially, it can be set as the startup folder. Now there is no such function. I hope it can be supported.

### Proposed solution

There is no place for the problem feedback pointer wheel to configure the middle button below the wheel. Officially, it can be set as the startup folder. Now there is no such function. I hope it can be supported.

### Alternatives considered

There is no place for the problem feedback pointer wheel to configure the middle button below the wheel. Officially, it can be set as the startup folder. Now there is no such function. I hope it can be supported.

### Related area(s)

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

### Additional context

_No response_

Start by tracing the existing button actions/remapping support and how MX Master 3 input is handled. Confirm how the middle button below the pointer wheel is exposed, what launching a startup folder should mean, and whether the behavior can be configured consistently. Done means the button can be assigned that action and the behavior is verified on the device.

Written by the indexing model from the issue text.