Adds a new apply_wallpaper command and its plumbing across
desktop, mobile, and Android. A WorkManager-based rotation
worker handles applying wallpapers in the background. Wallpaper
state now tracks currentId and imageIds for precise control.
- Introduced apply_wallpaper command across desktop, mobile and Android
- Added WorkManager-based rotation worker to apply wallpapers in the
background
- Extended wallpaper state with currentId and imageIds and updated schemas/permissions