Function sidereal_filter 

pub fn sidereal_filter(
    series: &[f64],
    period: Duration,
    options: SiderealFilterOptions,
) -> Result<SiderealFilterOutput, SiderealFilterError>

Remove a repeating residual component by phase-stacking prior repeats.

Samples are assigned to phase bins by (index * sample_interval) mod period. A correction is subtracted only after a phase bin has at least SiderealFilterOptions::min_coverage prior samples. Under-covered samples are returned unchanged and the corresponding phase bins are flagged.