edit: ah, found it! When I went into settings I noticed that "enable edit mode" was turned on, and turning it off fixed the issue.
I ran into a bug, or maybe just something that needs better instructions.
I bought a flooring option from the shop, and it appeared with a $ in the middle, a movement icon in the upper left, and a size-changing option in the lower right. I moved it & sized it how I wanted, but couldn't figure out how to get out of that mode so I tried selling it.
Then I noticed my original run also had those icons now, so I sold that as well.
Here's where I think it's a bug: when I tried to fill the food bowl I discovered that I could buy stuff, but I couldn't interact with anything. I can buy/move/resize/sell rugs, and I can buy but not move or sell anything else.
My poor kitties are hungry! Any advice? I just bought a copy for download but I'm hesitant to run it and risk getting it locked into this same floor-editing mode.