feat: sync 'experiments' #10

Use the preferences route to sync wiychsky.app settings between devices, instead of storing locally. Requires some investigation into how preferences are stored and likely patching the BskyAgent so that writing these requests can live behind the asynclock and avoid data loss.

https://github.com/a-viv-a/deer-social/issues/42 https://github.com/a-viv-a/deer-social/issues/41