fix(ride): teacher resident on cuda for displacement - labeling offloads it to cpu

Author: Ronald Tse

src/gpu/modal_distill.py

@@ -1246,6 +1246,10 @@ def _usable(ck: Path) -> bool:
         print(f"[{spec_id}] resume training from step-{step}", flush=True)
 
     if ride is not None:
+        # displacement needs the teacher resident on cuda for both the
+        # ridge fit and every training step (labeling offloads it)
+        teacher.to("cuda")
+        teacher.eval()
         # Ridge map per selected layer: teacher hidden space -> the
         # student's INITIAL hidden space (linearity preserves the
         # displacement through the projection). Fit on the first