feat(cli): text-to-speech v1 — select-encoding

[claude]

Adds the select-encoding recipe for text-to-speech v1 (cli).

Closes part of #176

[github-actions]

✅ CLI Recipe Tests

── recipes/cli/text-to-speech/v1/select-encoding ──
PASS
Generating speech with aura-2-thalia-en...
Audio saved to /tmp/deepgram_encoded.wav (149,804 bytes)
{
✓ PASSED