[Aeastr]

Adds a PosterBoard section for applying images through built-in wallpaper templates or replacing saved wallpaper artwork, with an option to restore the original. Also adds a reset option to recover from PosterBoard crashes (ran into some after leaving my custom wallpaper for a bit).

Tested on the on multiple simulators with Stripes and Bokeh templates, including HEIC input. macOS build passed; changed files pass SwiftLint.

Used for my app that makes wallpapers

[twostraws]

Thank you for this contribution! I'm a bit worried it seems like a hack – like this isn't something Apple would want us doing?

[Aeastr]

Oh hm I hadn't thought of it like this, was hyper-focused on getting app screenshots because the photo wallpaper flow doesn't work. This is definitely a workaround: it copies a built-in wallpaper template, replaces its artwork, and registers it in PosterBoard’s private store. I couldn’t find a supported way to do it, but I understand if that makes it unsuitable for Control Room