Make license text match metadata (CC BY-NC 4.0)

README.md

@@ -35,7 +35,7 @@ z = model.encode_sequence(seq, mask)   # [B, 128] cell-month embeddings
 ```
 
 ## License and attribution
-Model weights and code: CC BY 4.0. Training data is the UCDP GED (CC BY 4.0).
+Model weights and code: CC BY-NC 4.0. Training data is the UCDP GED (CC BY 4.0).
 If you use this model, cite UCDP:
 
 - Davies, S., Pettersson, T., Sollenberg, M., & Oberg, M. (2025). Organized violence