Share UART OTA logic between CLI and serve via POST /api/ota, WebSocket progress events, and a dashboard upload UI showing the running partition.
Co-authored-by: Cursor <cursoragent@cursor.com>
Serve polls the master over UART and pushes live state via WebSocket;
reopens the serial port when the device is unplugged and comes back.
Co-authored-by: Cursor <cursoragent@cursor.com>