Choices, choices, choices...
Well, you could straight out ask her. Tell her, with a straight face and in a normal, conversational tone of voice (if you can!) that you are confused and don't know whether she is flirting and coming on to you or whether you are imagining things. Ask her to clarify. And don't say anything further until she has completed her answer.
Let's be clear: in law, harassment is a course of conduct, not a single event -- unless it is something like "Baby, I want to fuck you and I'll fire you if you refuse."
Or, if I were in your shoes, I think I would have some fun. I'd continue to act totally "straight" but wait for opportunities to say something that can be taken in more than one way. A very subtle tease back (for example, if she asks you if she has a nice ass, ask her why your opinion matters to her or tell her that you can't be objective about her question) and put some questions into her mind. Then, be patient and wait. Do not make the first move: if she is really interested, she'll let you know. Wait until she makes a move or her contract expires.
Otherwise, the expression as I know it "Dog don't shit in his own doghouse."
But I do agree that people do regret what they did not do much more than the mistakes they made in doing something: "Nothing ventured, nothing gained!"
BTW, I assume you are single... if you are married you are playing with more fire than any person might be able to handle and you increase the chances of getting burned. That is, boy meets girl at the office is much easier for people to understand and accept than lecherous boss tries to seduce pretty young gal.
Perry