Thank you!
1. End turn hotkey is Shift+Enter. Since there's no "are you sure you want to end your turn, it had to be a two-key combo.
2. This is a good idea! I'll see if I can do that.
3. AI is a continual work in progress and fluctuates greatly between being clever and very silly. But! Though it was "impossible" for you, the enemy hero might have seen your hero including town defense benefits as challenging and thought there were better things to be done. The AI is better at attacking than at eliminating, which has become very clear when we do AI versus AI maps.
Yea it's more likely that the AI was just being silly :P