The "创建采购订单" button navigated to /purchase/orders/new which matched
the /:id detail route with id="new", causing the detail page to request a
non-existent order and render blank.
Added a dedicated new.tsx form page (supplier select, date, dynamic detail
rows with product autocomplete and computed line totals) and registered
/purchase/orders/new in .umirc.ts before the /:id route so it takes
precedence.
