Set Shipping Method
Saves the chosen shipping method on the cart and recollects totals. The response is the full updated cart so the UI can render new totals without another fetch.
Endpoint
| Endpoint | Method |
|---|---|
/api/admin/carts/{cartId}/shipping-methods | POST |
Sequence
The processor enforces: items, billing AND shipping addresses must already be present on the cart. Otherwise the call returns HTTP 409 with a precise message — Addresses must be saved before selecting a shipping method.

