Retrieves cost per person for the authenticated user's organization, one row per person,
for providers that attribute spend to a person at the source.

Cost only. Token counts, request counts and per-million figures have no source on this
path and come back absent rather than zero. Spend the provider attributes to nobody is
not a row here: it is carried under a named model sentinel on the models view.

provider: only anthropic_enterprise attributes spend to a person today, so any
other value returns an empty page rather than an error.

usageType: filtering narrows a person to that one type, and the provider writes
its non-token charges under their own type names, so a filter drops them from the
person's total. Omit it for a person's whole cost.

sort: totalCost (default, descending), userId, userEmail, percentage,
creditsApplied. These are the aggregate names, not the response field names, and an
unknown key fails the request.

All costs are in USD.