Whether you are worried about your dog, and/or about the helpful passerby with a crowbar who is worried about your dog, you have a friend in Elon Musk.
In fact, a couple of Tweets and the whole thing is handled. Or will be in one of those future software updates that are a way of life for Tesla owners.
People may not realize that electric cars already regulate the interior temperature, though the default is not all that great. Not fatal but not comfortable.
However, you can (already) set a comfortable temperature and leave it running. If you walk away from the car and forget, or if your errand is taking longer than expected, you can turn the AC on remotely. And unlike a gas vehicle, an electric car can pretty much sustain interior cooling indefinitely. Well many, many hours anyway. You can leave the music on too. It's always nice to have a preset though.
So you can do that now to protect your dog. Dog Mode will be designed to protect your $50,000 + Tesla from other dog lovers. So instead of taping a sign to the window with your cell number, you will be able to display the internal temperature and some kind of Dog is fine message on the big iPad that comes bolted to the Tesla's dash. Just don't tint your windows.