* ADD: CodeIO high quality dataset
Based on the dataset for CodeI/O. Annotated using Qwen-Coder and filtered based on the various metrics resulting in high quality filtered dataset, where approx 50% of the original data is kept.
* ADD: Compressed version
* Delete pure json version
* notebook for prepping first set of raw code files
* updated codeio processing notebook for repo-level processing
* fix for edge case in codeio scoring
* Add reformat notebook
* filtering pass
* add non-determinism filtering
* Tweak CodeIODataset & include first real data
* add basic codeio test, metadata
* 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
