A company is migrating a mission-critical application from an on-premises PostgreSQL 14 database to Azure. The database is 800 GB and uses several PostgreSQL-specific extensions, including PostGIS for geospatial queries. The solution must provide zone-redundant high availability with an automatic failover SLA of at least 99.99%, support the required extensions, and minimize administrative overhead such as patching and backups. Which Azure service should you recommend?