Fix edge feature layout handling for RGCN and edge updates

[benben951]

Summary

• keep the Payment Format column as the RGCN relation type even when ports or time deltas are enabled
• normalize all other edge features while preserving the categorical relation column for RGCN
• fix the edge update averaging in GINe, GATe, and PNA to match the node update residual averaging
• add regression tests for the edge feature layout helpers

Testing

• python -m unittest discover -s tests
• python -m compileall edge_feature_utils.py data_loading.py data_util.py models.py training.py tests/test_edge_feature_utils.py

Fixes #10
Fixes #8

[benben951]

Hi maintainers, I updated this PR to remove the accidental CRLF line-ending noise from the touched files. The review diff should now be much smaller and focused on the actual changes:

• Preserve Payment Format as the RGCN relation column even when ports/time-deltas are appended.
• Normalize only continuous edge features while leaving the categorical relation column intact for RGCN.
• Swap only the port columns for reverse message passing, instead of assuming the final two edge columns are always ports.
• Use the same residual averaging expression for edge updates as node updates.
• Add regression tests for the edge feature layout helpers and reverse-MP edge attributes.

Local verification after the cleanup:

• python -m compileall edge_feature_utils.py data_loading.py data_util.py models.py training.py tests/test_edge_feature_utils.py passes.
• python -m unittest discover -s tests could not run in my local lightweight environment because torch is not installed there (ModuleNotFoundError: No module named 'torch'). The tests are written against the project?s PyTorch dependency and should run in the normal project environment.

Could you please take another look when you have a chance? Happy to split this into smaller PRs if that would make review easier.