Load legacy checkpoints when Lightning passes weights_only=None.

app.py

@@ -7,7 +7,9 @@ try:  # torch>=2.6 flipped torch.load(weights_only) to True; legacy ckpts need F
         _torch_load_orig = _torch.load
 
         def _torch_load_compat(*args, **kwargs):
-            kwargs.setdefault("weights_only", False)
+            # Lightning passes weights_only=None, which torch reads as True
+            if kwargs.get("weights_only") is None:
+                kwargs["weights_only"] = False
             return _torch_load_orig(*args, **kwargs)
 
         _torch_load_compat.__harp_compat__ = True