Small board row, independent of T3's wire projection.
state is a T3 run status string, "idle", or "archived". Timestamps retain
their original ISO 8601 strings; no timezone or display formatting is applied.
__meta__ is internal reducer bookkeeping; retain it when caching rows. It is
excluded from Inspect and is not a board display field.
host is the caller's stable environment label, never inferred from a payload.