Add datasetSummary and compareDatasetSummary utilities

[stevevanhooser]

Summary

Add two new utility functions for dataset-level symmetry testing: datasetSummary creates a summary structure of an NDI Dataset object, and compareDatasetSummary compares two dataset summaries and returns a report of differences.

Key Changes

• New module dataset_summary.py: Implements datasetSummary() function that creates a summary dict containing numSessions, references, sessionIds, and sessionSummaries for an ndi.dataset.Dataset object
• New module compare_dataset_summary.py: Implements compareDatasetSummary() function that compares two dataset summaries and returns a list of human-readable difference strings, with support for excluding specific files and fields
• Updated ndi/util/__init__.py: Exports the new datasetSummary and compareDatasetSummary functions
• Updated MATLAB-Python bridge YAML: Added entries for both new functions documenting their MATLAB equivalents and signatures
• Comprehensive test suite: Added test_dataset_summary.py with 13 test cases covering empty datasets, single/multiple sessions, field validation, and comparison logic including session ID matching
• Refactored symmetry tests: Simplified dataset-level tests in test_build_dataset.py and test_download_ingested.py to use the new dataset-level utilities instead of manually iterating through sessions
• Removed helper function: Deleted _dataset_summary() helper from test_build_dataset.py in favor of the public utility

Implementation Details

• compareDatasetSummary delegates session-level comparisons to the existing compareSessionSummary function
• Session summaries are matched by sessionId rather than index order, allowing for flexible comparison even when session order differs
• Both functions support excludeFiles and excludeFields parameters for flexible comparison scenarios
• The implementation maintains exact parity with MATLAB equivalents as documented in the bridge YAML

https://claude.ai/code/session_01EctVW1VcbY2LzAdfZrGBB5