Pin kernels<0.15 to fix transformers hub_kernels LayerRepository error

requirements.txt

@@ -3,7 +3,10 @@ spaces>=0.30
 huggingface_hub>=0.30
 transformers>=4.55
 accelerate>=0.34
-kernels>=0.4
+# kernels 0.15+ introduced a mandatory revision/version kwarg on LayerRepository,
+# which transformers' hub_kernels module does not pass — pinning <0.15 avoids
+# the import-time ValueError on Space startup.
+kernels>=0.4,<0.15
 compressed-tensors>=0.7
 torch>=2.8
 rapidocr-onnxruntime>=1.4