one bug, one error, one request
bug, robot takes belt to target location to replace existing belt which is marked, but never does.

error, robots take belts to location, swap belts, then sit there because there is no place for them to take the old belt. (no storage chests defined)

request, a way to trigger this from the player. i would love to walk into an area and just press "upgrade" and everything near me gets checked and upgraded from my personal robots and supplies.

I like the idea of checking everything around the player. I'll look into that option.

I'll have to do more testing to recreate robots not placing. I know this was a tricky issue as I explored a variety of methods to try and balance reliability with performance.

Robots sitting around with items because no storage is normal. This can happen in vanilla if you deconstruct a tree or rock with no storage available.