[Feature Request] Layer-specific symmetry

The symmetry tool has been one of my most regularly used tools since its introduction since as a concept artist I'm often designing symmetrical things.

However, when I work I tend to have multiple drawings spread out on my canvas, and I'll bounce between them as I work, which means having to recreate the axis of symmetry whenever I do this.

I know I could just center everything on the same axis, but that would mean having to constantly hide/unhide whatever I'm not working on, and I'd also miss out on being able to view all the work at once.

So I'd love the ability to assign a unique axis of symmetry to an individual layer (or group!) that functions identically to the current tool, and then be able to (with a keyboard shortcut) toggle between the global symmetry I've defined and the layer-specific ones. And ideally, I'd be able to redraw any axis without affecting other existing ones, whether global or layer-specific.