Fix: rename 'eval_strategy' to 'evaluation_strategy' in TrainingArgum…

[trevorhughdavis]

🐛 Bugfix: Rename eval_strategy → evaluation_strategy in TrainingArguments

This PR corrects an API mismatch in the TrainingArguments dataclass where the constructor expected eval_strategy, but Trainer, config files, and CLI use evaluation_strategy.

✅ Changes

• Renames the field eval_strategy → evaluation_strategy
• Updates all internal logic and references
• Corrects docstrings and argument descriptions
• Validated via inspect.signature(TrainingArguments.__init__)
• Tested with full reinstallation and cache invalidation

🧪 Reproduction (Before Fix)

TrainingArguments(evaluation_strategy="epoch")
# ❌ TypeError: got an unexpected keyword argument 'evaluation_strategy'