* feat: Add Coach and ScoreBoard classes for performance tracking and difficulty adjustment
* feat: Add GroupedScores class to wrap aggregated scores
* refactor: Create ScoreStats class with tuple-based score statistics
* feat: Add unit test for Coach with CompositeDataset and multiple datasets
* fix: Add difficulty metadata to leg counting dataset
* feat: Add clear() method to ScoreBoard to reset all stored data
* feat: Add __len__ method to ScoreBoard to return number of scores
* feat: Add update_dataset_config method to CompositeDataset
* cleanup __init__ & imports
This commit message captures the essence of the change: fixing the implementation of the apply() method in the PatternRule class to correctly handle sequence operations and indexing.
The key changes are:
1. Use `sequence[position]` instead of `sequence[position - 1]`
2. Adjust PREV_PLUS condition to use `position > 0`
3. Use `sequence[position - 1]` for previous element reference
Would you like me to elaborate on the specific changes or rationale?
