_TasksLifecycleBaseSurface subgraph lifecycle as lifecycle protocol events.
Pushes LifecyclePayload to a StreamChannel named lifecycle.
The channel is auto-forwarded by the mux so payloads land in the
main event log under method = "lifecycle" (native transformer —
no custom: prefix) — visible to remote SDK clients over the
wire and to in-process consumers via run.lifecycle.
Tracks subgraphs at every depth strictly below the transformer's scope, so a graph → subgraph → subgraph chain produces lifecycle events for both nested levels in a flat stream.
Native transformer — projection key lifecycle is exposed as
run.lifecycle.