Girl has a boyfriend but seems very into me and I don't know what to do?

Keep in mind that we are both young so if this seems a bit childish it's because we're both early early 20s. Sorry

So there is a girl I work with and she seemed into me for months. She imitates a lot of my body language, she drunk texts me all the time, she asked our boss to put us on shifts together more often, she play hits me all the time, she talks about music all the time and will send me songs because we have the same taste, she looks at my location on snapchat, plus a ton of other shit. Once after work we got off at the same time and she pulled her car up to mine and we sat in the parking lot and talked for two and a half hours

Anyway despite all this, she has a boyfriend of about 6 months (though they were talking for 11 months) who started working with us a little while ago and I have no idea how to handle it. I didn't even know he existed until his first day. The boyfriend obviously sees me as a threat as he started imitating a lot of how I talk, he started wearing a watch and a chain like me, he's even started showing up to shifts when she's working with me to bring her stuff and stand around. What boggles my mind is that even when the 3 of us work together she'll talk to me as much as him and when she talks to him it's awkward and they don't really talk about much. I had several coworkers tell me that the two of them don't seem into each other which I normally brush off.

She even complains about guys that are too nice, guys that have long nails, etc... all stuff that applies to him

I don't really play into most of what she says or does though admittedly not all the time. She's asked me before to bring her food or a drink and I have refused every time and told her that it's incredibly inappropriate for her to ask that of me

Obviously this girl is no good. I'm not stupid but how do I handle this? Do I tell the boyfriend everything I know? Do I confront her about her behavior? Or maybe I'm just reading too far into everything and this is normal

Updates
+1 y
I forgot to add that she has opened up a great deal about her depression and insecurities. More so than what would seem normal
Girl has a boyfriend but seems very into me and I don't know what to do?
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