* fix(hyperframes-media): fall back to ffmpeg when ffprobe is missing
ffprobeDuration() returned NaN whenever the ffprobe spawn failed for any
reason, conflating "ffprobe binary not installed" with "file is corrupt".
Some ffmpeg-only distributions (common in curated Windows installs) ship
ffmpeg.exe without ffprobe.exe, so every TTS line hit the missing-binary
case and audio.mjs read the NaN as a bad WAV, silently dropping an already
successfully synthesized line. Now falls back to parsing ffmpeg's own
`Duration:` stderr banner when ffprobe specifically ENOENTs, and only
returns NaN when the file itself can't be probed by either tool.
* fix(hyperframes-media): update skills manifest for ffprobe fallback
