Summarize Busy Purchase Trends
busy_purchase_trend_summary
How it behaves
Use this when the user asks for a compact purchase, purchase-return, quantity, or voucher-count time series for one Busy company and financial year. Legacy group_by supports company, supplier, product/item, direct item group, and purchase material centre. Use dimension instead for a supplier or product standard/configured field resolved with busy_get_dimension_catalog, and dimension_filters for exact scoped filtering; never guess optional-field meanings. It ranks series across the complete selected period, zero-fills missing buckets, reports bucket growth and a trailing rolling average, and can combine non-leading series into Others. Amounts use pre-tax BUSY purchase item subtotals: purchases add and returns subtract. Use bounded purchase-register tools only for transaction evidence. Do not interpret mixed-product quantities as one unit or claim tax, landed cost, quality, lead time, or forecasting.