Add user-configurable TTS voice and tone style settings that flow from
the Flutter app through the backend to the voice-agent at call time.
## Flutter App (it0_app)
### Domain Layer
- app_settings.dart: Add `ttsVoice` (default: 'coral') and `ttsStyle`
(default: '') fields to AppSettings entity with copyWith support
### Data Layer
- settings_datasource.dart: Add SharedPreferences keys
`settings_tts_voice` and `settings_tts_style` for local persistence
in loadSettings(), saveSettings(), and clearSettings()
### Presentation Layer
- settings_providers.dart: Add `setTtsVoice()` and `setTtsStyle()`
methods to SettingsNotifier for Riverpod state management
- settings_page.dart: Add "语音" settings group between Notifications
and Security groups with:
- Voice picker: 13 OpenAI voices with gender/style labels
(e.g. "女 · 温暖", "男 · 沉稳", "中性") in a BottomSheet
- Style picker: 5 presets (专业干练/温柔耐心/轻松活泼/严肃正式/科幻AI)
as ChoiceChips + custom text input field + reset button
### Call Flow
- agent_call_page.dart: Send `tts_voice` and `tts_style` in the POST
body when requesting a LiveKit token at call initiation
## Backend
### voice-service (Python/FastAPI)
- livekit_token.py: Accept optional `tts_voice` and `tts_style` via
Pydantic TokenRequest body model; embed them in RoomAgentDispatch
metadata JSON alongside auth_header (backward compatible)
### voice-agent (Python/LiveKit Agents)
- agent.py: Extract `tts_voice` and `tts_style` from ctx.job.metadata;
use them when creating openai_plugin.TTS() — user-selected voice
overrides config default, user-selected style overrides default
instructions. Falls back to config defaults when not provided.
## Data Flow
Flutter Settings → SharedPreferences → POST /livekit/token body →
voice-service embeds in RoomAgentDispatch metadata →
voice-agent reads from ctx.job.metadata → TTS creation
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
hailin