I asked GPT 5.6 Sol Ultra to build an infinite canvas for HTML/React designs with layers, an inspector, and even real-time collaboration. It pretty much one-shotted the whole thing using planning + sub-agents. It burned through my limits (thanks for the resets!), but holy crap... it barely made any mistakes, and the design taste was way better than I'd expect. I spent almost no time fixing things. If this is where design tools are headed, designers/builders with good taste are going to have a…