Refactor the voice recording and playback systems to improve efficiency, reduce latency, and enhance Docker build performance.
- **Infrastructure**: Optimize Dockerfiles using build mounts for pnpm cache and reorder layers for better caching of dependencies and build tools.
- **Backend/Gateway**:
- Refactor `broadcast` module to use a generic event-based system instead of hardcoded functions.
- Simplify voice recording logic by merging metadata and segment management into a unified `segment.ts`.
- Optimize audio downsampling in `streamSetup.ts` using `Int16Array` views for better performance.
- Implement `withFallback` utility for more robust Redis/Database command execution.
- **Frontend**:
- Optimize audio playback visualization using pre-computed level shapes and efficient RMS calculation.
- Reduce latency in voice commands by prioritizing WebSocket communication over HTTP.
- Improve base64 encoding efficiency in audio transmission.
- **General**:
- Add default value for `ADMIN_PASSWORD` in shared config.
- Fix Docker healthcheck to use `127.0.0.1` instead of `localhost`.