Function assemble

assemble(
    plan: LiftPlan,
    outputs: readonly PortDef[],
    results: readonly (Readonly<Record<string, unknown>> | null)[],
): Map<string, FlowData>
Reassemble per-lane outputs into structured data, one entry per output port.
Parameters
- plan: LiftPlan
- outputs: readonly PortDef[]
- results: readonly (Readonly<Record<string, unknown>> | null)[]
Returns Map<string, FlowData>