Function run_mode_differential_regression 

pub fn run_mode_differential_regression(
    corpora: &[ModeDifferentialCorpus],
    comparisons: &[ModeComparison],
    options: &SnapshotDeterminismOptions,
    thresholds: ModeDifferentialThresholds,
) -> Result<ModeDifferentialRunReport, ModeDifferentialError>

Run pairwise mode differential comparisons across corpora.

This runner executes the same set of mode comparisons for every corpus, computes signal-level drift with deterministic normalization, and evaluates each pair against configurable thresholds suitable for CI gates.

Errors

Returns ModeDifferentialError if a corpus contains duplicate modes, is missing a required mode from comparisons, or snapshot comparison fails.