Fix classification transformer runtime compatibility issues

[DhruvrajSinhZala24]

Fixes #191

Summary

• update torchmetrics functional calls to use task="multiclass" for current versions
• replace the deprecated MPS availability check in utils.py
• remove the unsupported verbose=True argument from CosineAnnealingWarmRestarts
• add a project-level requirements.txt for the missing runtime dependencies
• document dependency installation in the project README

Validation

• ran python3 -m py_compile DeepLense_Classification_Transformers_Archil_Srivastava/eval.py DeepLense_Classification_Transformers_Archil_Srivastava/train.py DeepLense_Classification_Transformers_Archil_Srivastava/utils.py