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.
