Does anyone else think that the Black Knife hovering over her head that Min saw indicates that she will somehow get a hold of the knife ter'angreal that Aviendha identified as something that enables you to be invisible to evil?

I do not have enough information to figure out anything more complicated or detailed, but it seems from her behavior in the scene with Min and Cadsuane that she will do something independently that will help Rand, and she might need that ter'angreal to do it.

Here is the dull dagger's description for those who may not remember: The dagger is slightly longer than the palm of a hand, but wide in proportion. It is seemingly made of iron, but appears to also have never been sharpened, with an edge that would not cut much more than butter. The hilt is made of deerhorn and wrapped in gold wire. (Knife of Dreams, Chapter 15).

Min's Viewings aren't often hyper-detailed, so she may have only commented on the color of the dagger's blade, which being iron may be black, rather than the hilt.