- The stories supply what the app supplies rather than what a harness has
lying about: a microphone, and a call-sized root element.
- Invented device ids meant the menu asked for hardware that does not exist,
so the meter reported no microphone. A tone played into a real MediaStream
fixes it, and the meter runs its own analyser over it.
- Without a root element the list was bounded by Storybook's whole frame and
the menu ran off the canvas; without a call-sized one, four devices scrolled.
- Standalone specs: the switch that does not drop the call, the meter alive
while muted, the pinned meter, the focus ring.
- Component specs: the list sized to the call and not the window, resized
while open, every device reachable, and the modality belonging to one call.
- A headless browser has one microphone and one speaker, so fake-devices.ts
adds synthetic ones. It is explicit that it does not route audio.
