Furniture placement algorithms need work

The LLM-based furniture placement algorithm isn't very good at placing furniture (at least using our prompt configuration), and the _autointeriorblog_ and _random_ algorithms don't properly place furniture on walls/ceilings yet. Additionally, the _autointeriorblog_ furniture placement algorithm is slow when running in the browser; perhaps it could be tuned when running on the client, and if not, perhaps pushed to some async backend logic.