POST /voice-seed — writes or clears the seed for a named voice in
voices.json directly from the server, enabling the voice creator GUI
to save the chosen seed with one click.
Also updates find_best_seed.py to support --all-voices, per-voice
subdirectories, and the mixed DE/EN test sentence.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Generates WAV samples with different seeds for a given voice so the
user can listen and pick the most natural-sounding one. Uses the
server's hot-reload to switch seeds without restarting.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>