Workflow: create and operate an order

Read listCompanies and listProcessTemplates for Orders. createOrder resolves an explicit template first, otherwise the selected company's future-order default, then the process default. Record the order ETag. Use updateOrder, order stage/task actions, and completeOrder with current ETags and idempotency. Verify derived dates and history with listOrderActivity.

Expected state: one order owns a workflow snapshot; later company/template edits do not silently change it.