Allow additive fields from newer server revisions.
OptionalcollectionOptionalentityOptionallayerThe server's canonical SourceLocator.LayerId is string?
(honua-server/src/Honua.Core/Features/Geoprocessing/Domain/SourceBinding.cs).
Numeric forms (0) are accepted to match the SDK's historical
shape; both variants are coerced to a number inside
projectSourceBindings before hitting createDataset.
OptionalserviceOptionaltypeOptionalurl
Protocol-specific endpoint information attached to a binding.