feat(tts): add api endpoints and optimization for apple silicon

Introduce a comprehensive TTS/ASR module that:
- Adds /v1/tts-asr/config, /status, /warmup, /tts, /asr endpoints with detailed JSON responses
- Implements Apple‑Silicon detection, device selection (MPS/CUDA/CPU), and memory limiting logic
- Supports selectable model size, quantization, and offline mode via environment variables
- Adds robust audio validation and multi‑path resampling fallback
- Provides new README sections for API usage, device detection, and performance benchmarking
- Includes a full testing suite: unit tests, integration tests, macOS simulation and performance reports
- Updates backend dependencies and CI scripts
- Adds new front‑end views and components for Univer editor integration

All changes are backward compatible; new features are exposed through environment variables and new API routes.

backend/requirements.txt

@@ -1,4 +1,4 @@
-fastapi
+fastapi
 uvicorn
 ollama
 pydantic
@@ -18,3 +18,5 @@ soundfile
 numpy
 accelerate
 librosa
+psutil
+torchaudio