Constant DEFAULT_WINDOW_DAYS 

pub const DEFAULT_WINDOW_DAYS: u32 = 90;

Default trailing-window length (in days) for activity-scoped analyses. Anchored to the repo’s most recent commit date, not wall-clock time, so results are reproducible on archived repos. Used by any analysis that should focus on recent activity rather than full history. 90 days is the prevailing “active contributor” window in contributor-lifecycle research and long enough to smooth vacation/release-cycle gaps.