Creates an order tied to your platform via the auth token; the merchant
sees it under your platform's name in the POS app.

Customer handling

• The system looks up an existing customer by mobile under the
  merchant's company. If found, the order attaches to that record.
• If not found, a new Customer is created using the supplied name /
  email. Subsequent orders with the same mobile reuse it.
• Maldives‑format mobiles are normalized server-side
  (7771234 ≡ +9607771234).

Caveats

• An order starts in pending status with no bill. The merchant
  must accept the order in their POS for the bill to be generated.
  Until then, calls to POST /orders/{id}/payment will return 400.
• If you submit fees[], the location's auto-applied fees are
  dropped — your platform is treated as the source of truth for fees
  on its orders. Don't send fees: [] (empty) and expect Ewity's
  auto-fees to apply; only omit fees entirely.
• If a line has stock or availability issues at create time you get a
  400 with the failing item name. Use /validate first to surface
  these to the customer.
• Currency is the merchant's company currency (not your platform's).
  It's encoded in total_components labels via the merchant's
  settings.