V2.1 - DLR - PiMonitor app

Implement unified Pi telemetry system via rpiremote SSH proxy

- Reworked the entire data-gathering pipeline to fix Windows routing/forwarding issues
- Added dlr_dock_stats.py and dlr_car_stats.py scripts on the Pis for consistent JSON output
- Implemented chained SSH execution via rpiremote to reach rpidock and rpicar
- Updated Pi Monitor to display live CPU, RAM, temp, storage, voltage, and GPU clock
- Improved UI responsiveness
- System now works reliably even when direct Windows → Pi access fails