Stock account move reset to draft

This module extends the vendor bill (account.move) functionality in Odoo. Normally, once a vendor bill is posted and stock valuation layers (SVLs) are created, you cannot reset it to draft. This module changes that: it makes the 'Reset to Draft' button available for posted or cancelled vendor bills that have stock valuation layers on their lines.

When you reset such a bill to draft, the module checks each line that has stock valuation layers. If the inventory from the receipt has already been partially or fully consumed, it raises an error and prevents the reset. If the inventory is still fully available, it creates a new stock valuation layer with the opposite value to offset the original valuation difference. It also updates the product's cost for products using the average cost method.

This ensures that the accounting and inventory valuation stay consistent when you need to correct a vendor bill. The module depends on purchase_stock and works within the accounting and inventory modules.