* feat(cli): the api provider speaks the HeyGen audio analysis contract
The api rung now sends its key as x-api-key, a new Idempotency-Key on each
request, and 16 kHz mono 16-bit WAV: the channels are averaged and resampled
with a windowed sinc whose cutoff sits under 8 kHz, so nothing folds back in.
It reads the answer from a { "data": ... } envelope, or bare. Times stay in
seconds, and the answered times still snap onto beats measured on the signal
as decoded. The response type gains time_resolution_seconds.
* fix(cli): reject redirects from audio analysis requests
* fix(cli): preserve audio when stereo downmix cancels