Audio capture now produces per-channel FFT spectrum and RMS alongside
the existing mono mix. Each audio color strip source can select which
channel to visualize via a new "Channel" dropdown. This enables stereo
setups with separate left/right segments on the same LED strip.
Also shows the device LED count under the device selector in the target
editor for quick reference.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>