Sale Order Weight

This module changes the printed quotation/sale order report so that weight information is visible to customers and staff.

• In the product lines table of the report, a new "Weight" column appears after the unit price column. For each line, it shows the product's weight multiplied by the ordered quantity, using the weight unit configured in Odoo (for example kg) and the same decimal precision as the product weight field.
• Below the order lines, before the notes section, the report shows a "Total Weight" line with the sum of all line weights for the whole order.
• If a line has no weight (zero or no product), nothing is displayed for that line, and the total weight line is hidden when the total is zero.

The calculation is done through two helper methods added to sale.order and sale.order.line: the order method sums the weights of all its lines, and the line method multiplies each product's weight by its quantity. No new menus, buttons, or database fields are added; the change is limited to the sale order report template sale.report_saleorder_document.