Add SpeechGateway with Socket.IO namespace /speech for real-time
streaming transcription. Supports start-transcription, audio-chunk,
and stop-transcription events with session management, authentication,
and buffer size rate limiting. Includes 29 unit tests covering
authentication, session lifecycle, error handling, cleanup, and
client isolation.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add SpeechController with POST /api/speech/transcribe for audio
transcription and GET /api/speech/health for provider status.
Uses AudioValidationPipe for file upload validation and returns
results in standard { data: T } envelope.
Includes 10 unit tests covering transcribe with options, error
propagation, and all health status combinations.
Fixes#392
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add abstract BaseTTSProvider class that implements common OpenAI-compatible
TTS logic using the OpenAI SDK with configurable baseURL. Includes synthesize(),
listVoices(), and isHealthy() methods. Create TTS provider factory that
dynamically registers Kokoro (default), Chatterbox (premium), and Piper
(fallback) providers based on configuration. Update SpeechModule to use
the factory for TTS_PROVIDERS injection token.
Also fixes lint error in speaches-stt.provider.ts (Array<T> -> T[]).
30 tests added (22 base provider + 8 factory), all passing.
Fixes#391
