Weights in the invoices analysis view

This module extends the Invoices Analysis report (the pivot and graph view built on account.invoice.report) with a new numeric measure called Weight.

• The Weight value is calculated from each invoice line's product weight, multiplied by the line quantity and adjusted by the product's unit of measure conversion factors.
• For vendor bills, customer refunds and incoming receipts, the weight is shown as negative, so that the totals reflect the direction of the stock movement.
• If a product has no weight defined, the line contributes zero instead of causing an error.

The measure appears wherever the Invoices Analysis report is used, for example in the reporting menu under Accounting. Users can add Weight as a column or as the measure in pivot tables and graphs, group it by customer, product or period, and compare it with the invoiced amount or quantity.

The module only touches the account.invoice.report model and does not add menus, buttons, automated actions or scheduled jobs. It depends on the standard Accounting app and is intended for businesses that need to analyse the weight of goods they invoice or receive.