Add comprehensive docstrings to enable automatic documentation generation

[Copilot]

This PR addresses the issue where automatic documentation generation was failing due to missing or inadequate function docstrings throughout the repository.

Changes Made

Fixed Documentation Infrastructure

• Corrected API index: Replaced non-existent placeholder modules (math, greetings) with actual modules (utils, df_transforms, plots, figure_maker, generate_fake_dataset)
• Fixed import issues: Corrected relative import in generate_fake_dataset.py
• Installed dependencies: Added required packages (numpy, pandas, matplotlib, etc.) for successful module imports
• Removed non-existent functions: Cleaned up references to functions that don't exist

Added Comprehensive Docstrings

Added detailed NumPy/Google-style docstrings to 25+ key functions across all modules:

utils.py (15 functions):

• Performance calculation functions (get_session_performance, get_day_performance, etc.)
• Data validation utilities (column_checker)
• Text summary generators (get_text_from_subset_df, get_text_from_subject_df)
• Data loading utilities (load_example_data, get_outpath)
• Statistical analysis functions (get_right_bias, get_block_size_truncexp_mean30)

df_transforms.py (8 functions):

• Data preprocessing (fill_missing_data, get_dates_df, get_water_df)
• Behavioral analysis (get_repeat_or_alternate_series, get_performance_by_difficulty)
• Data transformation utilities (add_auditory_real_statistics)

plots.py (3 functions):

• Visualization utilities (training_calendar_plot, rasterize_plot, summary_text_plot)

figure_maker.py (2 functions):

• High-level figure generation (subject_progress_figure, session_summary_figure)

Documentation Quality

Each docstring now includes:

• Clear description of function purpose
• Complete parameter documentation with types
• Return value specifications
• Error conditions and exceptions
• Usage notes and implementation details
• Professional formatting following NumPy documentation standards

Verification

• ✅ Sphinx documentation builds successfully with minimal warnings
• ✅ All modules can be imported without errors
• ✅ Auto-generated API documentation displays properly
• ✅ Function signatures and descriptions appear correctly in HTML output

The automatic documentation system now works as intended, providing comprehensive API reference for all public functions in the behavioral analysis package.

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