Configuration and payloads

config.schema.json describes the complete Instance configuration. The Runner validates it before calling the SDK factory; the plugin still checks requirements that require contacting an external system.

Define Source and Sink payloads in proto3. A Source package contains a SourceRecordPayload root, a Sink contains a SinkRecordPayload root, and a combined package contains both. The descriptor, schema, manifest, executable, and README must describe the same Program.

The Program identity is the exact programName plus exactVersion. A semantic payload or behavior change needs a new exact version. Set the manifest display name and description explicitly; they are user-facing metadata and do not replace Program identity.