Intersected onto consumer-facing builder types to make withExtension
and getExtension uncallable (never). Using an intersection instead
of Omit preserves the class identity so extended builders remain
assignable to SchemaBuilder<any, any, any, any, any>.
Intersected onto consumer-facing builder types to make
withExtensionandgetExtensionuncallable (never). Using an intersection instead ofOmitpreserves the class identity so extended builders remain assignable toSchemaBuilder<any, any, any, any, any>.