Type Alias: PrinterAdapterMap
ts
type PrinterAdapterMap = Readonly<Record<string, PrinterAdapter>>;Map from engine role → PrinterAdapter for a connected device.
Single-engine drivers populate a 1-key record keyed by the engine's role (typically 'primary'). Multi-engine drivers (LW Duo: label + tape) populate one entry per drivable engine. Returned by each driver-web's requestPrinters() factory; the harness shell reads printers[selectedRole] to drive the active section.