pub fn roll_up(
summaries: &[FileUsageSummary],
pricing: &PricingTable,
now: OffsetDateTime,
) -> UsageReportExpand description
Roll per-file summaries up into the four windows the /usage
overlay drew. Windows are calendar periods relative to now, in
the same local timezone the day buckets already use: today, the
current week (from Monday), the current month (from the 1st), and
all-time. Each window carries both groupings and a total row, priced
via pricing (an unpriced model contributes 0 cost).