Tasks

Add requirement scenarios for configured microphone selection and tray runtime selection.
Add a failing behavior test for the tray microphone submenu.
Add a failing behavior test for configured/default microphone resolution.
Implement microphone device enumeration, selection state, and capture endpoint resolution.
Render the microphone submenu and execute microphone selection actions.
Update configuration documentation.
Run focused tests and openspec validate add-runtime-microphone-selection --strict.