Until last night.
A friend would wait until she was scooting by toward me, pick her up and have her walk to me instead. Twice, she took five whole steps! There were many witnesses and I was very proud. (I was also holding another girl's newborn, so that may have been incentive to get to me!) And I figured it was a two-person job - one to steady Heidi and send her off, and another person to encourage her forward. Turns out, she is quite happy to walk toward me even if I am the one setting her on her feet.
Here is video of her third time walking all on her own. As you can see, she is pretty excited, too!