My "friend" kissed my crush in front of me! How should I react?

So one of my friends kissed my crush yesterday while I was standing right beside her. We only just became friends recently. I've only known her for a week or two, because she just moved into the neighborhood. She knew I liked this guy and she repeatedly "assured" me that she wasn't interested in him. Yesterday I was talking to someone and she kept staring at me. When I walked away and came back to talk to her and my crush, she kissed him and ran off. It's like she purposely waited for me to come back and watch. Everyone knows I like the guy so everyone thought I was super sad, but actually I'm not. It wasn't like he and I were dating anyway. I'm actually not sad that he liked the kiss, I'm just disappointed that she lied to me about her feelings, completely disregarded my feelings, and kissed him right in front of me when she had many opportunities to do it while I was gone. Everyone thinks I should fight her, or confront her, or talk to my crush. I honestly don't know what to do. There's nothing for me to say to my crush. He already knows how I feel about him but he obviously doesn't feel the same way, but I can't force him to like me. I don't really see a point in talking to the girl. That would accomplish nothing. At least I know who my real friends are now and who I can trust. What should I do?
My "friend" kissed my crush in front of me! How should I react?
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