Adds Google Gemini TTS as the seventh voice provider, with 30 prebuilt
voices (Zephyr, Puck, Kore, Enceladus, Gacrux, etc.) and natural-language
prompt control. Integrates through the existing provider chain:
- tools/tts_tool.py: new _generate_gemini_tts() calls the
generativelanguage REST endpoint with responseModalities=[AUDIO],
wraps the returned 24kHz mono 16-bit PCM (L16) in a WAV RIFF header,
then ffmpeg-converts to MP3 or Opus depending on output extension.
For .ogg output, libopus is forced explicitly so Telegram voice
bubbles get Opus (ffmpeg defaults to Vorbis for .ogg).
- hermes_cli/tools_config.py: exposes 'Google Gemini TTS' as a provider
option in the curses-based 'hermes tools' UI.
- hermes_cli/setup.py: adds gemini to the setup wizard picker, tool
status display, and API key prompt branch (accepts existing
GEMINI_API_KEY or GOOGLE_API_KEY, falls back to Edge if neither set).
- tests/tools/test_tts_gemini.py: 15 unit tests covering WAV header
wrap correctness, env var fallback (GEMINI/GOOGLE), voice/model
overrides, snake_case vs camelCase inlineData handling, HTTP error
surfacing, and empty-audio edge cases.
- docs: TTS features page updated to list seven providers with the new
gemini config block and ffmpeg notes.
Live-tested against api key against gemini-2.5-flash-preview-tts: .wav,
.mp3, and Telegram-compatible .ogg (Opus codec) all produce valid
playable audio.
