fix: pass step parameter in TrackioTracker.log() (#3970)
TrackioTracker.log() accepts a step parameter but never forwards it
to self.run.log(), causing step values to be silently auto-incremented
instead of using the user-provided values.
All other trackers (WandB, TensorBoard, CometML, Aim, MLflow, SwanLab)
correctly pass step=step. This was simply missed when TrackioTracker
was added.
Fixes #3963
Made-with: Cursor
