SensorReadbackWidget

Read-only display of live sensor values for the active runtime.

Detailed description

Renders a compact grid of name + value (+ unit) labels, one per sensor declared by the active Preset. Values refresh in place when the consumer calls `setValue(index, double)` — typically wired to a SyncSection valueChanged signal so the widget repaints on every courier delta.

The widget is intentionally passive: it does not subscribe to any signal itself. The owner (StanzaControlActivity) does the wiring, keeping this widget unit-testable in isolation.