You are designing the data platform for a multitenant SaaS application on Azure SQL Database. The application currently serves 200 tenants, but the business expects rapid growth to several thousand tenants over the next two years. Each tenant's data must be isolated, individual tenants can vary greatly in size and activity, and the platform must scale horizontally without a single database becoming a bottleneck. The development team wants a Microsoft-supported way to manage tenant-to-database mapping and route queries to the correct database. Which approach should you recommend?