Restore torch/torchvision without version pin

ZeroGPU environment may not have torch pre-installed; removing it caused
silent Python startup failure. Use unpinned version to avoid conflicts.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

requirements.txt

@@ -13,6 +13,8 @@ pillow==11.3.0
 safetensors==0.6.2
 timm==1.0.20
 tokenizers==0.22.1
+torch
+torchvision
 torchdiffeq==0.2.5
 torchsde==0.2.6
 tqdm==4.67.1