Feature Request: have desktop use roms & saves on phone/external memory when connected; "docking" feature

Hi, since RetroArch is cross-platform, I'm sure many are using RetroArch on more than one platform. However, for those who play on a desktop OS but also play on a portable version, they might want to play the same roms with the same saves across all the platforms they use. I'd like to see perhaps RetroArch's desktop version scan for a connected phone/external memory drive with RetroArch installed, and use the same roms and saves on there instead of having to copy paste everything all the time. Perhaps there could be some sort of cache file RetroArch makes on the phone/external storage that the desktop version could read, so the program could know exactly which folders the roms and saves are located in. Basically docking your phone to play the same roms and saves from your phone on your desktop.

The issue names no files, tests, or entry points. Start by locating how RetroArch handles ROM and save paths on desktop and portable storage, then define the docking workflow and acceptance tests for connected-device detection and shared files.