Stock Picking Return Restricted Qty

This module adds a new checkbox called "Restrict Return Quantity" on the configuration form of operation types (the screen where you set up incoming, outgoing and internal operations). The checkbox appears right after the return operation type field.

When the option is enabled for the operation type used by a transfer, the return process behaves differently:

• The return wizard automatically fills in the returnable quantity based on how much of the original move has not already been returned, so users see the maximum they can send back.
• If a user tries to type a larger quantity, Odoo immediately shows an error saying that returning more quantities than delivered is not allowed.
• The same check runs again when the return is confirmed, so the restriction cannot be bypassed.

The calculation looks at the original move quantity and subtracts quantities already returned through related moves that are partially available, assigned or done, never going below zero.

It touches the stock operation type configuration, the return picking wizard and its lines. No new menus or reports are added; the change is visible inside existing stock screens and the return wizard.