Create a purchase order (commande fournisseur / bon de commande)
Opens a new purchase order (bon de commande) for a supplier (fournisseur) + shop with the ordered per-SKU quantities and their unit cost in cents. The order starts open with every line unreceived. The supplier is validated. 404s for an unknown supplier; 409s when the order id already exists.
Authorizations
Authorization: Bearer <token>. Accepts EITHER a Keycloak access token (scopes-in-token) OR an opaque POS session token; both resolve to the same pos.* scope vocabulary the route guards enforce.
Body
Caller-supplied unique order id (409 if it already exists).
1Supplier (fournisseur) the order is placed with.
1Store (magasin) the goods are ordered for.
1The ordered lines (commande fournisseur); at least one.
1Response
The created purchase order (status open).

