Include local microphone audio in recordings by default

[Copilot]

Recordings captured loopback/system audio but could miss the local speaker because most meeting apps do not play the user’s microphone back through output audio. This made saved meeting audio contain the other participant while omitting the recorder’s own voice.

• Recording defaults

  • Enable microphone mixing by default via Config.include_microphone = True.
  • Preserve explicit loopback-only recording with --no-include-mic.
  • Keep --include-mic as a compatible explicit opt-in flag.

• Capture behavior

  • Mix the selected/default microphone into the loopback stream before transcription and WAV export.
  • Fall back to loopback-only recording with a warning if microphone capture is unavailable.

• CLI and docs

  • Update start and tray argument handling for the new default.
  • Refresh README examples around microphone gain, device selection, and loopback-only mode.

Example usage:

# Includes your microphone by default
python recorder.py start

# Adjust local mic level
python recorder.py start --mic-gain 1.5

# Record only system/loopback audio
python recorder.py start --no-include-mic