Canonical message shape that Gralkor expects at its port boundary.

One shape, three roles. Adapters normalise their harness's events into this form before calling the configured client's capture/5, /6, or /7.

• :role — "user" | "assistant" | "behaviour". behaviour collapses thinking, tool calls, tool results, and any other harness-internal activity into a single role; Gralkor does not branch on interior shape beyond role.

• :content — a string. Adapters choose how to render their events; In implicit-default mode Gralkor renders user and assistant content into the captured transcript and uses role labels in recall context. A selected Lens's ingestion process decides how its captured messages are persisted.