Stock Picking Purchase Order Link

This module makes it easier to move between a warehouse transfer and the purchase order behind it.

On the transfer form (the screen used for receipts, deliveries and internal transfers), a new smart button labelled "Purchase Order" appears in the button box at the top, with a shopping-cart icon. It is only visible when the transfer is actually linked to a purchase order, and it is shown to users with warehouse rights.

Clicking the button opens the related purchase order in form view, so the user can check supplier, ordered quantities, prices and status without searching manually.

• The button is added to the standard transfer form, so it appears on receipts created from purchase orders.
• It is hidden when there is no linked purchase order.
• It is restricted to the stock user group.

The module only extends the stock.picking model with the action that opens the purchase order; it does not change quantities, validations, or any automatic behaviour. It relies on the standard link between transfers and purchase orders provided by purchase_stock.