Everyone lives in yurts.
Most homes are compounds comprised of multiple yurts inside of a circular wall, though some people can only afford a single yurt, with partitions inside to break up the space and provide privacy.
The round shape provides no corners, though some care has to be give for where the wall and roof meet.
For added protection, look at our line of incense and other spirit wards.
Really late edit:
So I was looking this answer over and had another thought. Getting the spirits to not stick around by creative architecture is a good defensive strategy, but what kind of offensive strategy could be used?
One idea I came up with was to use the spirits known tenancies against them and build traps.
So you make a square box with the right dimensions and put them a little way outside of the village. When the sun comes up the spirit goes into the box to rest. Then you load the box onto a catapult and launch it. The box would be constructed in such a way that it would fall to pieces once it is launched, and since the spirit isn't affected by gravity and has nothing to hold on to, it will be launched into space never to return.
So, Ghostbusters with catapults.