Unified plotting function for engagement metrics with privacy-aware options.
Arguments
- data
A tibble containing the data to plot
- metric
Column name for the metric to plot (default: "session_ct")
- student_col
Column name for student identification (default: "name")
- facet_by
Faceting option: "section", "transcript_file", or "none" (default: "section")
- mask_by
Masking option: "name" or "rank" (default: "name")
- privacy_level
Privacy level for data visualization (default: from global option)
- metrics_lookup_df
Optional lookup table for metric names (default: NULL)