Adds --capture-mic/--mic-output for a second, independently-captured audio
track (mic vs system, written to separate outputs to avoid interleaving
corruption). Embeds Info.plist at link time so the binary carries a stable
CFBundleIdentifier and the usage-description keys TCC requires, and adds
scripts/build-signed.sh + scripts/create-signing-identity.sh so a rebuilt
binary keeps the same signing identity instead of losing granted
permissions on every rebuild.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>