feat(cli): text-to-speech v1 — generate-audio

[claude]

Adds the generate-audio recipe for text-to-speech v1 (cli).

Closes part of #176

[github-actions]

✅ CLI Recipe Tests

── recipes/cli/text-to-speech/v1/generate-audio ──
PASS
Generating speech with aura-2-thalia-en...
Audio saved to /tmp/deepgram_output.mp3 (21,456 bytes)
{
✓ PASSED