[FEATURE]: Education AI Suite - Settings modal window to select microphone for Smart Classroom sample app

Created by: ashwinvijayakumar

Description Extend the Settings modal to allow users to select their preferred audio input source for the Smart Classroom sample app. The modal should offer a dropdown or radio button group to choose between:

• Audio file upload (default)
• Enumerated microphone devices

The actual recording controls and real-time transcription will be handled elsewhere in the GUI.

Assumptions

• Audio input source selection is a configuration step, not an interaction point.
• Microphone enumeration is supported via browser APIs (e.g., navigator.mediaDevices.enumerateDevices()).
• The selected input source will be passed to the main window for interaction.

Dependencies

• Audio pipeline (ASR, diarization)
• GUI framework support enumerations of microphones

Expected Output

Settings modal with:

• Audio input source selector (file vs. mic)
• Dropdown listing available microphones (if mic is selected)
• Save/Apply button to persist selection

Acceptance Criteria

• Modal displays available audio input options
• Microphones are enumerated and selectable
• Selection is saved and reflected in main window behavior
• File upload remains default for October release