Retrieves a per-day breakdown of cost and credits applied for the authenticated user's
        organization, grouped by (date, provider, model).

        Returns a flat list of rows (one per date × provider × model) plus organization-wide
        envelope totals. Suitable for timeseries charts and burn-down analyses.

        All costs and credits are in USD. `creditsApplied` is null on rows where no credits data
        is available. The envelope `totalCreditsApplied` is null only when no row in the page
        has a non-null value.