Per-Monitor Wallpaper Override Support

[MilkyTech]

First of all, thank you for LittleBigMouse—it's hands down the cleanest and most reliable tool I've used for multi-monitor input mapping.

I had a feature idea that I think would fit in nicely with your existing functionality, especially since the app already has direct access to monitor layout and display awareness.

Idea:
Add support for per-monitor wallpaper overrides, with selfish reasonsn in mind:
Allow setting a solid color or custom static wallpaper for a secondary display.
Allow ignoring or overriding the system-wide slideshow for selected monitors (e.g., keep slideshow on Monitor 1, override Monitor 2
with a black background).

Windows 10/11 doesn’t provide native per-monitor control (at least when using slideshow mode)—any background changes affect all monitors. Display Fusion supports it, but only for $$$. Since LBM already tracks and adjusts monitor layouts dynamically, it seems a logical extension to push a background override at the per-monitor level.

Thanks again for your work!