Being young, in your "dream job" and then being told "there’s someone waiting outside to collect your corp devices" without any real explanation. It's 100% HR + Managers fault that this situation has escalated to this.
If a future employer asks for a reference from Google she's screwed.
This whole "don't say anything bad about X, it will reflect badly on you" is how the Epsteins and Weinsteins of the world go undetected for years.
If what she says is true she should probably go to a lawyer and sue.