Helping someone write an automatic ascension bot is terrible motivation for adding access to the encounters list, so that's not happening (unless, as was the case with visit_url, you help satiate a curiosity I have ... and I have no curiosities at the moment, so that option's out ^_~). Anyway, while it's not easy to get at the information you want, it's not impossible.
What you can do is setup a combat consult script which sets a user property to indicate that a battle occurred and then completes the battle using the player's preferred combat tactic. Before every adventure, blank out the property and set a different property indicating the player's preferred combat tactic. If it's set after coming back from an adventure, you know a battle happened. If it's not set, well, a noncombat happened.
The castle has well-defined patterns to what kinds of noncombat actions happen, and every one of them, save two, gives item drops. One of them gives stat gains. Because you're in hardcore, these stat gains ALWAYS give you a full stat point. Track all of this. If no stat point change happens and no items dropped, you obviously hit the wheel.