Active-active order consistency

Design an active-active multi-region order system for a food-delivery marketplace where both the diner and the restaurant for a given order are pinned to one metro (so a given order's writes naturally belong to one region), but a small fraction of entities are cross-metro (a chain restaurant operating in two metros, a corporate account spanning regions). Both regions accept writes. The requirement: an order's lifecycle (placed → accepted → preparing → en route → delivered) must be strongly consistent and never see two regions concurrently advancing the same order, while the system stays fully available in each region if the inter-region link drops. Define the write-ownership model, how a write that lands in the 'wrong' region is handled, and what happens to the cross-metro entities during a partition.