I was perplexed about why I would setup TV on XB1. I have a family that doesn't want to fire up the Xbox in order to watch their shows.
It seems like a no brainer now, but I even contacted Xbox Support on Twitter and came back with no way to have it both ways.
I bought a RocketFish HDMI splitter from Best Buy for about $70 and split the signal coming from my DirecTV DVR to the Xbox and also directly to my TV. This solved the issue and is working perfectly. I can watch TV normally (and managed by universal remote) but I can also take advantage of the snap feature while waiting to get into races in Forza (which can take 15 minutes).