feat(examples): add Python and browser WebSocket clients ...

- examples/client_python.py: streaming TTS client with sounddevice playback
- examples/client_browser.html: Web Audio API based browser client
- docs/05_usage.md: usage instructions for both clients
- pyproject.toml: optional client extras (websockets, sounddevice)
- requirements.txt: commented note about client deps

Initial voice TTS server with F5-TTS backend, WebSocket streaming and warm-up ...

- FastAPI WebSocket API for real-time chunked TTS

- F5-TTS GPU backend with reference caching and auto-transcription

- Dummy backend for offline tests

- Streaming text segmenter, session state, stop/resume

- Startup warm-up, PCM16/base64 audio, basic tests

- Documentation: architecture, protocol, usage, roadmap, technical notes